Abstract: Artificial inoculation tests are conducted on Masson pine of different ages and growth vigorwith PWN severed from the adults of Monochamus alternatus and cultured by Botrytis cinerea on PDA.Results showed that young Masson pine(under 14 years) with exuberant growth vigor has strong resistance to PWN, but pine over 16 year-old and with weak growth vigor──with middle, mature andover-mature Masson pine sound──has nonresistunce to PWN.Masson pine over 16 years has strongnegative correlations betweent age class and resistuncibility. Some terpene fractions and resin acid composition of different-aged Masson pine correlated with the resistance against PWN.The test resultsshowed that the content of longifolene,2-copaene and dehydroabietic acid increased with Masson’spine age, showing a negative correlation with resistance against PWN.Young Masson’s pine with highresistance has no 2-copanene and low content of longifolene and dehydroabietic acid. As the Masson’spine age increased the content of β-pinene, monoterpene and abietic-type resin decreased, showing apositive correlation with the resistance against PWN. Young Masson pine with high resistance has highcontent of β-pinene, monoterpene and abietic-type resin acid. Similar resultS were obtained from theculturing PWN on PDA of Botrytis cinerea by using the several compounds above.High content of β-pinene, monoterpene and abietic-type resin acid and low content of longifolene and dehydroabietic acid(the young Masson’s Pine have) can curtail PWN’s propegation.