Using linseed oil and hydrogen peroxide as raw materials, three epoxy linseed oils with epoxy values of 1.16mmol/g, 1.52mmol/g and 2.32mmol/g were synthesized first, and then esterified with quantitative phosphoric acid to synthesize LCF-P1 and LCF-P2 and LCF-P3 three combined oxidized-phosphate linseed oil leather fatliquors. It was applied to leather fatliquoring, and the effect of different degrees of epoxidation on the fatliquoring performance of oxidized-phosphorylated leather fatliquors was explored, and the fatliquoring effect was compared with the commercial phosphate fatliquors. SEM was used to observe the morphology of collagen fibers in the cross section of leather before and after fatliquoring. The experimental results show that LCF-P2, a fatliquor with an epoxy value of 1.52mmol/g, shows good fatliquoring performance, the softness of the grey leather after fatliquoring reached 10 mm, the tensile strength was 35.91 N/mm2, the tear strength was 49.56 N/mm and the thickening rate of leather was 24.36%. In leather thickening rate, mechanical strength improvement slightly better than the market phosphate fatliquoring agent.