The compositions of odor gases in Jizhuangzi sewage treatment plant of Tianjin in the summer of 2011 and 2012 were monitored by GC-MS. Meanwhile 24 subjects (11 male, 13 female) were selected for acute exposure experiment by HOLTER. 67 kinds of odors were detected out, the concentration of odor gases emitted from grid was the highest, sulfide and oxygen-contained were major species of odor gases; the acute exposure experiment at the grid showed that blood pressure reacted normal, maximum heart rate was significantly higher than normal value, mostly in the field test period, while the HRV parameters all deviated from normal range, which indicated that malodorous gases induced the subjects' sympathetic nerve activity. According to health risks assessment of odor gases from sewage treatment plan, methylene chloride and benzene of malodorous gases in the sludge dewatering had potential risk, non-carcinogenic hazard index (HI) was less than 1, within an acceptable range.