Impacts of Time Allocation, Companionship by Parents and Peers on Psychological Health of Adolescents Abstract The increased leisure time has brought about the inevitable changes to the social development and the progress of science and technology. Further alleviation of students’ homework, can also enable them to enjoy much more free time. Extra-curricular leisure time is a double-edged sword, which has both positive and negative impact to the cultivation for the mental health of teenagers. How to allocate extracurricular time, and how to better stay together with adolescents have an important impact on the healthy and comprehensive development. This study aims to help adolescents and their parents to choose the correct leisure from the view point of time allocation on adolescents mental health. This study adopts an questionnaire on Chinese youth’s extracurricular time allocation and parental company. This paper discusses the influence of extracurricular time allocation on adolescents mental health through CES-D and YSR, paying attention to the parental company to the interaction on the activities time. The study is based on the cross-sectional data of national youth mental health database in 2009, for 4,394 of the sixth grade to high school students (male 50.04%, age 15.45±2.39 years) data for analysis provided by Institute of Psychology, Chinese Academy of Sciences. The questionnaire on Allocation of Time was made by the adolescents. The questionnaire on CES-D and YSR was estimated by teenagers themselves. Family income was reported by the parents. The main results of this study are as follows: 1. Moderate time spent on independent learning activities and more time on leisure activities actively, such as sports, housework and other interesting class activities can relieve depression and reduce externalizing problems. 2. The none-sports leisure time with depression and externalizing problems are significantly positive correlation. The extension of time, especially the none-sports time such as surfing internet or playing other electronic games, will worsen depressed mood, and it can also increase the externalizing behaviors. 3. Parental companion can relieve the depression of the activities and reduce externalizing problems. 4. Moderate companionship by the peers after school in academic independent study, sports and reading can reduce depression. But doing homework assigned by teachers, surfing the Internet, playing electronic games and enjoying outdoor sports together with peers will increase externalizing problems. Conclusion: Adolescents depression and externalizing problems in China and the extracurricular activities time allocation are significantly correlated. Accompanied by parents in extracurricular time is conducive to mental health of teenagers. But only some activities are appropriate to be done with peers, and the time should be time properly controlled.