Abstract: This paper studied the effects of different fertilizer models on simulation for the3414 fertilizer experiments, which were conducted from 1995 to 1998 in Tangshan City in Hebei Province, sponsored by UNDP (United Nations Development Program) The results showed that,the success ratio of simulation by threefactor and onefactor model was 56% and 100%, respectively; the recommended fertilizer amount by threefactor model simulation was higher than that by onefactor model simulation in the same '3414' experiment; and the ratio of the experiments without N, P2O5 and K2O recommended by onefactor model simulation was 15%, 44% and 67% , respectively But by the threefactor model simulation, such information was not available So, in '3414' fertilizer experiment, the onefactor model was a supplement and an optimization for the threefactor model 