The effect of biogas slurry and organic fertilizer on the loss of P and K in rice field was studied，and the bestmeasures to reduce the loss of P and K weresought.A pot experiment was carried out on the paddy soil of TaihuLake.Sixtreatments were setup:blank control(CK)，conventional fertilizer(CF)，100% biogas liquid nitrogen replacement(N1)，75% biogas liquid+25% pig manure organic nitrogen replacement(N2)，50% biogas liquid+50% pig manure organicnitrogen replacement(N3)and 100% pig manure organic nitrogen replacement(N4).The results showed that the amount ofphosphorus loss in runoff of each fertilization treatment wasN4>N3>N1>CF>N2，among which N4 treatment was thehighest， reaching P 44.99 kg/hm²，N2 treatment was thelowest，which was only P 3.94 kg/hm²and 8.76% of theformer.The amountof K loss in runoff of each fertilization treatment wasN1>N3>N4>N2>CF，the highest was K 43.48 kg/hm²of N1treatment， the lowest was K 24.78 kg/hm²ofCF.There was no significant difference in the yield of different fertilizationtreatments.Ina comprehensivecomparison，N2 treatment can significantly reduce the risk of runoff phosphorus and potassium loss on thebasis of maintaining a certainyield，which is a more suitable fertilization mode.