Abstract: In order to meet the large demand for instant, temperature resistant and salt resistant polymers in offshore oil field development, research on ultra-high molecular weight temperature resistant and salt resistant lotion polymers was carried out. The super high molecular weight, instant, temperature resistant and salt resistant lotion polymer was prepared by using self-made high efficient polymer emulsifier and self-made heat stabilizer and low-temperature composite initiation system. Studied the effects of preparation process, co solvents, functional monomers, and thermal stabilizers on product performance. The results show that the molecular weight can be 22 million to 24 million through process optimization. Urea and sodium sulfate can significantly improve the dissolution rate of ultra-high molecular weight temperature resistant and salt resistant lotion polymer. Adding N,N-dimethylacrylamide, self-made heat stabilizer and sodium 2-acrylamide-2-methylpropane sulfonate during polymerization can significantly improve the temperature resistance and salt resistance of the product. The structure and properties of ultra-high molecular weight temperature resistant and salt resistant lotion polymers were characterized by electron microscopy, laser particle size analyzer, GPC and TGA. The research results indicate that the prepared polymer latex has uniform particle distribution, narrow molecular weight distribution, and good temperature resistance. The viscosity retention rate of the polymer lotion in one month is more than 90% at 35000 mg/L salinity and 75 ℃. Ultra high molecular weight temperature resistant and salt resistant lotion polymer has instant solubility, high molecular weight, good temperature resistance and salt resistance, and can be widely used in offshore oil field development.