Abstract:Dastarcus helophoroides is an important natural enemy of longicorn. In order to know that the control effect of parasitism of D. helophoroides, we breeded D. helophoroides when they were babies, which are advantageous to Monochamus alternatus ’parasitism. According to the parasitism rate and the rate of degeneration of M. alternatus, the control effect of the D. helophoroides on M.alternatus was studied. The results showed that the average population reduction rate in 2019 was 46.20%, and 66.7% had a parasitic rate higher than 50%; in 2020, the control effect was 33.18%, and the parasitism rate was 34.91%.It can be seen that the release of D. helophoroides has obvious control effect on M. alternatus in the pine forest, the parasitism is good, the number of M. alternatus in the treatment area has been reduced, and the control effect of M. alternatus is generally better.