Water is the lifeblood of agriculture, drought and groundwater in North China's serious overexploitation, efficient use of water resources to become the focus of attention. Research shows that, agricultural irrigation water consumption of about 50% in the field, strengthen the research and development of water-saving technology, can significantly reduce the amount of irrigation, improve the efficiency of rainwater utilization and crop yield. Polyacrylamide (PAM) as a soil conditioner, can increase the cohesion of the soil surface particles, maintain good soil structure, prevent soil crust, increase soil infiltration, prevent soil erosion, reduce soil water evaporation, improve water utilization, with conserving soil and water, fertilizer, yield, thermal insulation equivalent; polyacrylamide can improve the fertilizer utilization rate, improve the ecological environment. At present, the depth of polyacrylamide infiltration and runoff and the mechanism of soil and water conservation research into the soil, and the soil water and fertilizer, etc. because of its high cost and not get promoted, carry out polyacrylamide application in agricultural production in arid and semi arid regions, has important significance to improve the efficiency, water saving irrigation with irrigation water and natural precipitation. Polyacrylamide is a water-soluble linear polymer, the monomer acrylamide (AM), almost insoluble in benzene, ether, ester and other organic solvents, soluble in water, is currently the most widely used water-soluble polymer. Polyacrylamide as colorless granule solution for viscous liquid, nearly transparent, non-toxic, non corrosive, at 150 DEG C to thermal decomposition in the environment, good stability. A cationic, anionic, nonionic, zwitterionic and other types of ultra high molecular weight polyacrylamide, with different polymerization degree, with molecular weight ranging from 500 to 24000000 Da (Da represents a 12C atomic mass 1/12) between changes. Polyacrylamide have special physical and chemical properties, can be used as flocculant, thickening agent, drag reduction agent, mud treatment agent, surface active agent, soil conditioner, water moisturizing agent, seed coating agent, paper strength agent has been widely used in oil extraction, water treatment, textile, papermaking, medicine, agriculture and so on. The molecular formula is C3H5ON (polyacrylamide) n, has strong flocculation. Polyacrylamide when in contact with water, because the hydrophobic hydrophobic interaction to inner granular structure, the formation of insoluble hydrophilic groups, through the combination of hydrogen bonds with water molecules to form hydrate water. The molecular structure of the three-dimensional network of polyacrylamide COOH group on water dissociation, produce COO and H+ ions, because the polymer chain of COO to water diffusion, the concentration of H+, concentration of H+ in the network is higher than that of water, the concentration difference, the high molecular weight polymer water to infiltrate the network outside the network inside, in order to achieve the balance of internal and external network H+ concentration, so the network structure and the osmotic pressure, the water molecules in the role of osmotic pressure to the net net hole water permeability formation. The mesh free water water is bound by space polymer network, physical and chemical properties of water molecules but this bound is ordinary water, only limit the movement of water molecules. Application of Polyacrylamide in the soil, the formation of many "small reservoir", when drought, "reservoir" due to osmotic pressure and slowly release water for crop absorption and utilization, so as to effectively prevent moisture loss and evaporation, soil moisture and drought reached. Polyacrylamide molecules dissolved in water in the soil, interaction with soil particles, to a certain role in promoting the formation of soil aggregates, the soil sedimentation coefficient, structure coefficient and levels of water stable aggregates volume increased significantly, and increased soil water infiltration rate, hinder the formation of soil crust, reduce surface the runoff, provide the conditions for crop production. The test shows that Mao Jianhua, 51.3% ~ 0.1mm polyacrylamide can reduce the particles size of 62.5%.