Abstract: Effect of adding different concentrations of N, P and K in substrate of its composition with turf: vermiculite = 4: 1 on seedling growth of marigold and petunia were studied by the orthogonal test. The results showed that effects of seedling growth of two kinds of flowers were different among N, P and K with various concentrations ratio. Two kinds of flowers grew rapidly in seedling substrates with low N and middle P and K （0.1 Kg/m3 N、0.4 Kg/m3 P2O5、0.4 Kg/m3 K2O）, and also grew rapidly in seedling substrates with low N and high P and K（0.1 Kg/m3 N、0.8 Kg/m3 P2O5、0.8Kg/m3 K2O）. The effects of these substrates approach or exceed those of imported substrate. Marigold seedling grew most rapidly in seedling substrates with low N , middle P and high K（N 0.2 kg/m3、P2O5 0.4 kg/m3、K2O 0.8 kg/m3）, while petunia seedling grew most rapidly in seedling substrates with middle N and high P and K（N 0.4 kg/m3、P2O5 0.8 kg/m3、K2O 0.8 kg/m3）