Abstract  [Aim]  Through a long evolutionary process, a kind of interdependent and restrictive relationship has formed between insects and hosts. It is this unity of opposites in nature that maintains the relative stability of insect and host populations. Therefore, biological control requires information not only on the occurrence law and population dynamics of pests but also on the population dynamics of natural enemies and the correlation between pests and natural enemies. [Methods]  In this study, 6 sites were used to investigate the population density of Gynaephora qinghaiensis and the natural parasitism rates of two natural enemies (Pteromalus sanjiangyuanicus and Chaetogena gynaephorae) of G. qinghaiensis pupae for 5 years (from 2015 to 2019) in Yushu Prefecture, Qinghai Province. Meanwhile, the correlations between the natural parasitism rates of the two natural enemies and the population density of G. qinghaiensis were analyzed. [Results]  The population density of G. qinghaiensis ranged from 1.0 to 78.4 ind./m², the natural parasitism rate of P. sanjiangyuanicus was 9.2%-25.0%, and the natural parasitism rate of C. gynaephorae was 0.7%-4.4%. Moreover, the parasitism of G. qinghaiensis by P. sanjiangyuanicus was male biased. There was a significant negative correlation between the parasitism rate of P. sanjiangyuanicus and the population density of G. qinghaiensis in the next year (P<0.05). [Conclusion]  The results revealed that P. sanjiangyuanicus had a significant inhibitory effect on the population growth of G. qinghaiensis and was suitable as the dominant natural enemy for the biological control of G. qinghaiensis. Studying the relationship between the parasitic natural enemies and population growth of G. qinghaiensis provides a scientific basis for the selection and propagation of parasitic natural enemies of this species in relation to biological control.