The objective of this study is to determine the life cycle of wheat spike weevil Pachtychius hordei (Brulle) Coleoptera, curculionidae in El-Marj region in the East of Libya during 2015 to 2016. The study is applied on weeds and grain crops fields (wheat and barley). By field visiting every two weeks from Mid-February to harvesting time (end of May) it also continued after harvesting season. According to the obtained results, P. hordie distributed on all El-Marj regions, on Fam. Graminea (weeds, Barley and Wheat), the adults are feeding on leaves, which laying one egg in the grain (Lactic stage, ¼ of grain size), hatched larva feed on the grain and at the end it moves to the soil to pupate, in the next season emerges as adult. It has one generation each year, but some adults have a summer dormancy. They stay alive to the next season but become pale, and start laying eggs on weeds and early plants of wheat and barley and then they invade all the field.