Abstract: This paper deals with the correlation analysis in population density of Matsucoccus matsumurae and bark type as well as chemical content of 5 resistant and 3 susceptible provenances of Pinus massoniana. Results showed that bark type played a major role to show that whether a provenance was resistant to the insect or not. Nymph populations, under the same condition, were found to be significantly higher in provenances with thinner bark than that with thicker bark. There is a correlation coefficient up to -0.8786. Analysis of 29 chemical contents showed significant differences between resistant and susceptible provenances. Total sugar and free amino acids were markedly higher in the susceptible ones, especially the isoleucine, lysine and alanine.