Abstract: The research aimed to investigate the effects of different N，P，K fertilizer ratio and fertilizer amount on sweet maize yield. “3414” design theory was applied to set sweet maize fertilizer efficiency test in Hannan modern agricultural experiment and demonstration garden of Wuhan city. The yield of N2P3K2 was the highest，reaching 13 477.5 kg/hm2，when that of no fertilizer N0P0K0 treatment was 10 870.5 kg/hm2. The difference of yield was significant. Compared with the different dosage of nitrogen and phosphorus and potassium，it was found that while the other two fertilizes kept unchanged only increased a single use of another fertilizer，the sweet maize yields increased with the fertilizer at first and then decreased when continued to improve the amount of the fertilizer treatments. The results showed that the treatment without potassium had a notable effect on sweet maize yield. Contrasted with the nutrients deficiency no phosphorus treatment had less effect on sweet maize yield and no nitrogen treatment had minimal effect on sweet maize yield. Optimum fertilizing proportion of N，P and K fertilizer and fertilization amount had a direct impact on sweet maize yield. Potassium fertilizer was the key factors. It should be consideration of the reasonable application of fertilizer in fields.

Key words: “3414” field experiments, sweet maize, fertilization, yield