Take front-line ground staff of airline companies for example, the main topic of the study is to discuss the relationship among employment status(full-time & part-time),organization commitment, citizenship role identity and organizational citizenship behavior and the confounding effect of job security on the relationships among the above variables. We hope that airline companies can understand the relationship between job attitude and job behavior of employees of different employment status so that it can be the references for them to adopt flexible human resources strategies. The questionnaire survey was adopted for the study. The samples are the front-line ground staff of airline companies in Taoyuan international airport, including passenger agents and cargo agents and so on. There were total 360 questionnaires released, and 242 of them are valid samples, including 167 full-time employees and 75 part-time employees. Through statistics analysis, the main results of the study are¡G 1. Employment status has no positively correlations with organizational citizenship behavior and citizenship role identity but had positively correlations with continuance organization commitment. We think the main reason is that the benefit package of full time and part-time ground staff in airline companies is not different very much and part time ground employees have the chances to become full time. On the other hand, the flexible work schedule can satisfy part time employees¡¦ other needs. So considering the job attitude and job behavior, full time and part time ground staff will not be very different. 2.Organization commitment has positively correlations with organizational citizenship behavior and will affect it in a positive way. The affective commitment has significant prediction on organizational citizenship behavior while continuance commitment has least prediction on it. 3. Citizenship role identity has positively correlations with organizational citizenship behavior and will affect it in a positive way. Employees with more organizationally-benefit citizenship role identity will be more likely to do organizationally-benefit citizenship behavior while employees with more individually-benefit citizenship role identity will be more likely to do individually-benefit citizenship behavior. 4. Job security has negative confounding effect on the relationship between employment status and citizenship role identity. We think that in a low job security situation, part-time ground staff will be with more citizenship role identity and do more organizational citizenship behavior in order to keep the job. Based on the above conclusions, this study offers some suggestions as the references for the airline companies. Key Words¡GEmployment Status, Part-time, Organization Commitment, Citizenship Role identity, Organizational Citizenship Behavior, Job Security