This research was conducted to develop a composite diet and compare its effects on developmental time, fecundity, survival rate, and life table parameters of pistachio green stink bug,Brachynema germariKolenati (Hemiptera: Pentatomidae) with a natural diet. The biological parameters of this pest were investigated using two-sex, age-stage life table theory on both composite and natural diets (25 ± 1°C, 50 ± 10% relative humidity, and a photoperiod of 16:8 [L:D] h). Based on the preliminary studies, the combination of the green beans (Phaseolus vulgarisL.), sunflower seeds (Helianthus annuusL.), and wild rue capsules (Peganum harmalaL.) was introduced into a composite diet. There was no significant difference between the longevity of each stage on diet treatments, but the mean fecundity of female fed on composite diet was about 196.48 ± 12.02 (eggs), which indicated a significant decrease than the fecundity of female fed on the natural diet (265.81 ± 11.67 eggs;P = 0.05,t-test). Also, main parameters of life table (r,R,T, and λ) for composite and natural diets were about 0.0863 ± 0.0031 d, 89.03 ± 13.33 eggs, 51.987 ± 0.536 d, and 1.091 ± 0.0034 dand 0.1023 ± 0.003 d, 128.75 ± 17.56 eggs, 47.454 ± 0.439 d, and 1.1077 ± 0.0037 d, respectively. There was a significant difference between these four parameters on both diets. Despite a significant decrease in fecundity with using composite diets, this diet can satisfy our needs now and the laboratory rearing of pistachio green stink bug did not stop over the year in the absence of host weeds and insect did not diapause.