In order to provide a theoretical basis for the application of modified phosphate fertilizer double active diammonium which mainly included diammonium phosphate and lignin in mung bean production,four phosphorus levels,namely P0(no phosphorus),P1(diammonium phosphate,225 kg/ha),and P2(double active diammonium,225 kg/ha) and P3(1/2 double active diammonium,112.5 kg/ha)were applied on Lüfeng 2 and Lüfeng 5 mung bean genotypes.Mung bean dry weight,root morphology,photosynthetic physiological characteristics and yield were calculated.The results indicated that both P2 and P3 treatments increased the plant dry weight of mung bean during V3—R6 stage compared to the P0 and P1 treatments,and the maximum value appeared in P3 treatment at R6 stage. Compared with the P0 and P1 treatments,Lüfeng 2 aboveground dry weight increased by 57.55% and 34.31%,and the root dry weight increased by 19.63% and 11.84%.The performance of Lüfeng 5 was similar to that of Lüfeng 2,with 30.29% and 21.62% increase in aboveground dry weight,and 36.66% and 34.56% increase in root dry weight.P2 and P3 treatments significantly increased mung bean total root length,total root surface area at R4 stage,increased average root diameter at V5 stage and total root volume at R4 stage,and significantlyenhanced net photosynthetic rate of Lüfeng 2 and Lüfeng 5 at R6 stage. Both P2 and P3 treatments increased plant soluble protein content of Lüfeng 2 at R4 stage and decreased simultaneously it at R6 stage.They also increased leaf soluble protein content of Lüfeng 5 at R4 stage and significantly decreased acid phosphatase activities in the leaf and root at R2 and R6 stages,respectively.P2 and P3 treatments could increase stem thickness of Lüfeng 2 and plant height of Lüfeng 5,and also increase the number of grainsper plant,the hundred grains weight and the weight of grains per plant of two genotypes. The number of grains per plant,the hundred grains weight and the weight of grains per plant of P3 treatment in Lüfeng 2 were 14.85% and 48.28%,15.41% and 13.26%,16.94% and 44.16% higher than those of the P0 and P1 treatments,respectively;and those of P3 treatment in Lüfeng 5 were 46.51% and 11.35%,3.34%and 8.70%,51.20% and 28.20% higher than those of the P0 and P1 treatments,respectively.It can be seen that modified diammonium phosphate can effectively promote the growth of mung bean plants,and improve plant stress resistance by increasing the content of soluble protein,promote the accumulation of photosynthetic products at the later stages by increasing the photosynthetic capacity,and finally increase the mung bean yield.