Abstract: In order to study the effect of physiological characteristics in the seedling of Castanopsis fissa Rehd.et Wils under different basic fertilizer levels, the one year seedling was the experimental material. As to provide theoretical basis for choosing basic fertilizer, put the seedlings in different phosphate fertilizer levels, the compound fertilizer the urea and ck, tested some physiological indexes——the ultra oxygen anion content, the SOD and POD activity, the chlorophyll content and net photosynthetic rate——in seasonal change after fertilization. The results showed that the phosphate fertilizer, in low and medium concentration,could promoted the physiological activities in the seedling of Castanopsis fissa Rehd.et Wils. Therefore, It was the suitable type and concentration of basic fertilizer in the seedling of Castanopsis fissa Rehd.et Wils that fertilized superphosphate (including effective P2O516 %) 25-50 t per hm2,which could increased its protective enzyme activity, the chlorophyll content and net photosynthetic rate, reduced the ultra oxygen anion content.