Abstract: Objective The aim of this study was to examine the effects of different movement intensities and continuous movement time on the heart rate,energy expenditure and metabolic equivalent of energy,muscle strength,muscle endurance and cardiorespiratory system of junior high school students,and to provide scientific references for having physical exercise scientifically,and for improving students' physical quality.Methods Totally 226 students from 6 classes of a middle school in Shanghai were selected to participate in an experiment in the last 8 weeks.The exercises of different intensity and lasting time were offered in physical education class.The 6 classes were provided with 15-minute continuous exercises of great and moderate intensity,10-minute continuous exercises of great and moderate intensity and 5-minute ones.Results The differences in average HR,EE and MET in PE classes were found of statistical significance(F=18.634,8.562,8.162,P<0.01).By paired-samples t test,the students in experimental class 1 were shown to have significant different GBMI and SU,those in class 1,2,3 and 5 were indicated to have significant difference in FVC and ER,while the students in class 4 had a significant difference in ER(P<0.05).Conclusion The larger time of continuous movement and the more intensive movement were offered to the students in the physical education class,the larger increament of exercise load they have got.The exercise load should be controlled in a stable interval during the physical education class.