Abstract: [Objective] This research aims to measure the amount of body water, fat, total sugar, protein, glycogen content and trehalase activity of male and female adults of Lygus pratensis (L.) in non-overwintering period and overwintering period in order to explore the changes of content of non-overwintering stage and wintering period Lygus pratensis(L.) biochemical substances so that a better understanding of its overwintering mechanism will be obtained in the hope of providing theoretical basis for integrated control of Lygus pratensis (L.).[Method]The change law of cold resistance of Lygus pratensis(L.) was studied by acquiring female and male adults of Lygus pratensis (L.) at different developmental stages and determinating biochemical matter contents.[Result]From non-wintering period to overwintering period, the Lygus pratensis (L.) adult body fat content increased gradually and tended to be stable, total sugar content and glycogen content firstly increased and then decreased, the protein content decreased first and then increased, but the trehalase activity rose at first and after that period, it began to fall down.[Conclusion]There is a certain connection between cold hardiness and dynamic change of biochemical matter contents of Lygus pratensis (L.) adults during non-winterring period and overwinterring period, which implies the ecological adaptability to such changes as light and temperature.