Abstract: Previous research shows that there exists a common system deviation in social comparison. University students and in-service employees taken as the research subjects, a test is made to check their better than average effect and bias-blind-spot effect. The results are as follows: university students and in-service employees are found to have an obviously better performance in terms of the two effects in social comparison; Also, the students’ bias is significantly more obvious than that of the in-service employees; In addition, the personality traits such as confidence have certain influence upon their better-than-average effect, while personality traits exert no significant influence upon the bias blind spot effect.