Based on the universal rotary composition designing method of 4 factors and 5 levels, the effects of applications of nitrogen, phosphate, potassium and density on the yield and number of flowers and net photosynthetic rate (Pn) of herb chrysanthemum were studied. The results indicated that N, K, P applications and the density affected the yield and Pn significantly. N positively affected significantly on No. of flowers per plant and the weight of single flower, and K also had a little affect, but other factors showed weak effects. In terms of effect on yield, the order was of N>density>K>P; while in terms of effect on Pn, the order was N >K>density>P. The reasonable yield can be obtained when the application rates of N, P2O5 and K2O ranged within 339.5 - 384.7 kg/hm2, 161.2 - 195.7 kg/hm2 and K2O 291.5 - 344.0 kg/hm2, respectively, while the density ranged within (5.5 ~ 6.0)×104 plants/hm2. The reasonable proportion of N, P2O5, K2O in formulated fertilization should be 1:0.51:0.89.