Abstract: Under low and high P application,32 Maize genotypes were selected to study the genotypic differences in biological characteristics and P efficiency.Multiple linear regression analyses and clustering of maize genotypes for P efficiency and relative biological characteristics were conducted,and seedling for tolerance to low phosphate stress was screened.The main results were summarized as follows: 1) The variation of relative plant height(RPH),relative plant dry weight(RPW),relative root dry weight(RRW) and relative leaf age(RLA) among genotypes were 0.309-0.978,0.314-0.947,0.367-1.400 and 0.455-0.790,respectively,the variation of P efficiency,absorption efficiency and utilization efficiency among genotypes were 0.196-0.935,0.879-4.235 and 0.621-1.764,respectively.2) Partial regression coefficient of relative root dry weight(RRW) to P efficiency was significant and the optimum regression equation was Y=-0.087+0.702X3 (P0.05,R2=0.6549).Partial regression coefficients of absorption efficiency and utilization efficiency to P efficiency were also significant and the optimum regression equation was Y=-0.379+0.2749 X1+0.301 X2(P0.05,R2=0.7390).3) Only inbred lines 178 and 082 had the characteristics of high P efficiency and high relative biological characteristics,while most of studied inbred lines belonged to moderate and low ones.