Asynacta ambrostomae Liao is an important parasitoid of the Ambrostoma quadriimpressum Motschulsky egg, which is an important monophagous pest of the Ulmus pumila Elm. However, the biological and ecological characteristics of Asynacta ambrostomae Liao have had little coverage. In order to define the utilization value and biological control potential of Asynacta ambrostomae, we have investigated the natural parasitic rate, sex ratio, reproductive type, number of wasps per host egg and body length of Asynacta ambrostomae. At the same time, the laboratory population life table of Asynacta ambrostomae was established by calculating longevity, survival rate and adult reproduction. The results showed that the wasps were lagging behind the egg stage of the Ambrostoma quadriimpressum. The average parasitic rate of Asynacta ambrostomae Liao was only around 33%, when Ambrostoma quadriimpressum Motschulsky were in peak oviposition period; its average parasitic rate was 89.2% when the host was in the post-oviposition stage. During nurture, the number of wasps per host egg was 2.92, and the average sex ratio was 3.64:1(female:male); the type of reproduction in wasps was sexual reproduction, although it can perform parthenogenesis, and the offspring are pure males. The experimental populations were kept in the laboratory and fed on a 20% honey solution, 20% sucrose solution and water; meanwhile we provided no additional nutrition as CK. Through the construction of population life tables for the Asynacta ambrostomae experimental population at different stages of nutrition, six parameters were obtained, including net reproduction, generation average period, intrinsic rate of increase, finite rate of increase, oviposition per female and population doubling time, which revealed the effects of nutrition on the growth and development, life expectancy and fecundities of Asynacta ambrostomae. The results showed that different nutritional conditions have a significant influence on male and female longevity, and the total egg quantity of females in the treatment was significantly different from the control. Their life tables of laboratory population at different stages in nutrition at 25℃ were constructed. The research has shown that with additional nutrition, Asynacta ambrostomae has a strong reproduction ability and a great population growth potential. A single female can lay 148.58,130.54 and 113.54 eggs (20% honey water,20% sucrose water, pure water), which was significantly greater than the control group (89 eggs). The net reproductive rate (R₀) of Asynacta ambrostomae treated with 20% honey water,20% sucrose water, pure water and no additional nutrition were 74.42, 65.27, 56.77 and 44.50, respectively, and the intrinsic growth potentials (r_m) were 0.33, 0.32, 0.31 and 0.29, respectively. The life expectancy of a generation was around 13.0d at room temperature, which indicated that providing nutrition could significantly improve its fecundity and the insect populations can increase rapidly in a short period of time. This study will help the development and utilization of Asynacta ambrostomae for the biological control of Ambrostoma quadriimpressum.