Abstract: Objective To investigate and analyze the degree and source of working stress in a power supply enterprise. Methods Using stratified random sampling method, questionnaire survey was conducted among employees in four departments of Shenzhen Power Supply Bureau： substation, transmission, district power supply bureau, and functional department. The contents of the investigation included demographic characteristics, degree and source of occupational stress and so on. Chi-square test and ordered multiple classification logistic regression were used to explore occupational stress and related factors in the power supply enterprise. Results A total of 1 508 people were investigated, of whom 1 383 questionnaires were included in the statistical analysis, accounting for 27.54% of the total number of employees in Shenzhen Power Supply Bureau （1 383/5 022）.Their average age was 36 years old and the male to female sex ratio was 3.17∶1. Of the respondents, 62.11% had undergraduate degree, 70.35% were married, and 45.12% worked for less than 10 years. The average length of working age was 14 years. Of 1309 employees, 94.6% had different degrees of occupational stress. Sources of occupational stress were overload （65.5%）, low pay （50.1%）, fast pace of work （39.0%）, customer complaints （25.9%）, poor working environment （19.0%）, and tense interpersonal relationship among colleagues （7.5%）. The ordered multi-classification logistic regression analysis showed that overload （OR=4.05）, fast pace of work （OR=4.24）, customer complaints （OR=2.41）, poor working environment （OR=1.50）, low pay （OR=1.67）, and 10 to 29 years of working age （OR=2.01,2.09） were risk factors for the severity of occupational stress （P < 0.05 or P< 0.01）.Conclusion Occupational stress existed in most employees in Shenzhen power supply enterprises. It is suggested to formulate accurate stress relief strategies according to different sources of occupational stress.