Abstract: Objective The morphology and biology of Pristiphora conjugata (Dahlbom) were studied to lay a basis for controlling this pest. Method The morphology, life history and effects of temperature on adult life-span of Pristiphora conjugata were studied in both laboratory and field. Result The results showed that P. conjugata has 6 generations per year in Wuqing district of Tianjin and it took 2038 days to complete one generation. The pupae of P. conjugata overwinter in top soil or at the base of trees. The newly-hatched larvae of the first generation were observed on April 25th and the generations overlapped from May to September. The mature larvae pupate inside a cocoon in the soil in late September. The larvae have enormous appetite and gregarious. The temperature has significant effect on adult life-span of P. conjugata:the high temperature (30℃, 25℃) was unfavorable to its survival, and adults have the longest life-span under 20℃ condition. Conclusion P. conjugata has 6 generations per year in Tianjin and the temperature has significant effect on adult life-span.