A method for extracting and purifying Gastric Lipase by using immobilized horse antibody, comprising the steps of: S1: placing a single colony of lipase-producing Pseudomonas ATCC21808 in a 250-mL shake flask containing 25 mL of shake-flask culture solution, and at 28° C. 200rpm for 20h, then transfer into the fermentation medium at 10% of the inoculum, and cultivate for 68h at 28°C and 200rpm to obtain a fermentation broth; wherein, each liter of the shake flask broth includes: 5g of yeast extract , peptone 5g, vegetable oil 10g, the balance is water; pH value is 7.0; each liter of fermentation broth includes: yeast extract 10g, peptone 5g, NaCl 0.5g, vegetable oil 10g, the balance is water; pH value is 7.0; S2: centrifuge the fermentation broth, collect the supernatant, and obtain the crude lipase enzyme liquid; wherein, the centrifugation adopts a high-speed refrigerated centrifuge, centrifuged at 4°C and 10800g for 15 minutes; S3: immobilize the crude Gastric Lipase enzyme liquid on the Horse antibody column, during the column loading, the Gastric Lipase activity of the effluent was detected until there was Gastric Lipase activity, and the loading was stopped; then the column was washed with a 0.1M disodium hydrogen phosphate-potassium dihydrogen phosphate buffer with a pH value of 7.2 , and then eluted with 0.1M disodium hydrogen phosphate-citric acid buffer with a pH value of 3, and collected the eluate to obtain the Gastric Lipase after purification of Chemicalbook; Disodium hydrogen phosphate-potassium dihydrogen phosphate buffer is used to wash the column to neutrality, and the solution is also used to adjust the eluent to a pH value of 7; wherein, the preparation method of the immobilized horse antibody column comprises the steps of: selecting 4 Mongolian horses ( The weight and corresponding age are: 240kg and age 3 years, 290kg and 5 years old, 320kg and 7 years old, 360kg and 10 years old), each Immunization once every two weeks for a total of 12 weeks of immunization, 2 mL each time, with a dose of 15 mg Gastric Lipase plus the same amount of Freund’s complete adjuvant, subcutaneous immunization at multiple points, and the antiserum was collected after the antibody titer was more than 1:10000 detected by ELISA. ; Centrifuge the antiserum to remove cellular components and other precipitates, collect the supernatant, and purify the polyclonal antibody using a proteinA or proteinG affinity chromatography column; connect the polyclonal antibody to the activated Sepharose2B to obtain an immobilized horse antibody column; S4: adding polyethylene glycol to the purified lipase to precipitate the lipase; then centrifuging to collect the precipitate; lyophilizing the precipitate after dialysis to obtain Gastric Lipase, the enzyme activity is determined to reach 150,000-250,000 units/g ; Among them, centrifugation is centrifuged at 4°C and 000g for 8min.