Interview is the most frequently-used method of selection in present enterprises. In order to select suitable employees, there will be at least two phases of interviews in which both of line managers and hr specialists are interviewers. There is no existing literature discussing about the differences between their behaviors during interviews. This study is mainly focused on those differences between interview questions asked by line managers and hr specialists in a cooperative interview. Besides, this study also analyses relevant factors which have impacts on effectiveness of interviews and corporation. This study uses dyadic questionnaires to collect empirical data and the author selects both line managers and hr specialists to answer the dyadic questionnaires. To increase validity of data, there is a limitation on the process of sample selection. Only those line managers from manufacture department or business divisions which are the major profit resource in enterprises can answer the questionnaires. 180 dyadic questionnaires were sent, and 114 valid questionnaires were responded. The valid response rate was 63.33%. Using independent-sample T test, one-way ANOVA and two-way ANOVA, the results are shown as below, 1.The effectiveness of interviews is irrelevant to interview training, interview period and interview check list. 2.There is no difference between interview questions asked by line managers and hr specialists. 3.There is no significant influence on interview questions between line managers and hr specialists by interview training, interviewer¡¦s interview experience and method of interview cooperation. 4.The effectiveness of cooperation is not influenced by interview training and interviewers¡¦ interview experiences either.