Abstract: This study was carried out in order to explore the effect on chlorophyll content of Pinus yunnanensis seedlings by different concentration of nitrogen and phosphorus foliar spraying. Two years P. yunnanensis seedlings were used as test materials by using experiment design of nitrogen(N) and phosphorus(P) with 3 levels of 2 factors. Nitrogen and phosphorus foliar fertilization were sprayed. The results showed that the different concentration of nitrogen and phosphorus foliar spraying influenced chlorophyll content for P. yunnanensis seedlings. Moderate nitrogen and low phosphorus can effectively promote the chlorophyll a, chlorophyll b and chlorophyll(a + b) content for P. yunnanensis seedling. Nitrogen and phosphorus foliar spraying changed the accumulation speed of chlorophyll a and chlorophyll b. And the relative growth relationship changed with the growth of P. yunnanensis seedling. In the case of fertilization of phosphorus accumulation rate of chlorophyll a, when compared to the chlorophyll b, showed that the first increased and then decreased. But the change were more complexly when the fertilization of nitrogen, or combination of nitrogen and phosphorus. By applying relationship between the dosage of nitrogen and phosphorus, and chlorophyll content, the regression equations were built. The appropriate nitrogen and phosphorus sprayed were gained by the effect analyses of single factor. Totally, nitrogen and phosphorus foliar spraying can promote chlorophyll content for P. yunnanensis seedling. Low phosphorus and moderate nitrogen was helpful for the increase of chlorophyll content for P. yunnanensis seedling. Nitrogen was the leading factor for the increasing of chlorophyll content for P. yunnanensis seedling. The relative growth relationship between chlorophyll a and chlorophyll b varied with the dosage of nitrogen and phosphorus, and test time.