In order to explore the effects of chemical substances changes in damaged masson pine(Pinus massoniana) needles on population dynamics of Dendrolimus kikuchii,D. kikuchii larvae were reared with P. massoniana needles with different damage degrees(mild,moderate and severe),and its population parameters and contents of nutrients and secondary substances in damaged P. massoniana needles were measured,and the integrated correlation coefficient was adopted for data analysis. The results showed that with the damage degree aggravating,flavones in needles increased accordingly,while contents of soluble sugars,polysaccharides and proteins decreased. The average developmental duration and mortality of D. kikuchii larvae increased with the damage degree increasing. No significant correlation was found between the changes in contents of tannins or total phenols and the developmental duration or mortality of each instar larvae. There were significant direct and integrated correlations between contents of nutrients and secondary substances of P. massoniana needles and the developmental duration or mortality of each instar larvae except the 6thinstar larvae. With the damage degree increasing,all parameters of D. kikuchii population including body weight of the 7thinstar larvae,average feeding capacity of larvae,pupal weight,pupation rate,female ratio and fecundity decreased. No significant correlation was found between the changes in contents of tannins or total phenols and population parameters of D. kikuchii larvae. The results suggest that the contents of nutrients and secondary substances in P. massoniana needles dramatically influenced the population parameters of D. kikuchii,and the importance from high to low successively was soluble sugars > proteins > polysaccharides > flavones. Contents of tannins and total phenols seemed to have little influence. In order to explore the effects of chemical mass changes in damaged masson pine (Pinus massoniana) needles on population dynamics of Dendrolimus kikuchii, D. kikuchii larvae were reared with P. massoniana needles with different damage degrees (mild, moderate and severe), and its population parameters and contents of nutrients and secondary substances in damaged P. massoniana needles were measured, and the integrated correlation coefficient was adopted for data analysis. The results showed that with the damage degree aggravating, flavones in needles increased accordingly, while contents of soluble The average developmental duration and mortality of D. kikuchii larvae increased with the damage degree increasing. No significant correlation found between the changes in contents of tannins or total phenols and the developmental duration or mortality of each instar larvae There were significant direct and integrated correlations between conte nts of nutrients and secondary substances of P. massoniana needles and the developmental duration or mortality of each instar larvae except the 6th instar larvae. With the damage degree increasing, all parameters of D. kikuchii population including body weight of the 7th instar larvae, average feeding capacity of larvae, pupal weight, pupation rate, female ratio and fecundity decreased. No significant correlation found in the changes in contents of tannins or total phenols and population parameters of D. kikuchii larvae. The results suggest that the contents of nutrients and secondary substances in P. massoniana needles dramatically influenced the population parameters of D. kikuchii, and the importance from high to low increased was soluble sugars> proteins> polysaccharides> flavones. Contents of tannins and total phenols seemed to have little influence.