For increasing competitions of department stores, how to reinforce the extent of selling skills of salespeople will affect individual or organizational achievement performance strongly. This study was intended to explore the relationships between selling skills and achievement performance of the salespeople. In this study, work experience, training and locus of control are independent variables, achievement performance is dependent variables, and the selling skills are as a mediator. This study examined the mediator effect of the salespeople¡¦s selling skills among of the work experience, training and locus of control. Besides, we defined the product type and reward as a moderator between the job experience, training as well as locos of control. The subject of this study is 316 salespeople of a department store in Kaohsiung. This research used the method of questionnaire. The results indicated that: 1. Training was positive significant to selling skills. 2. Training was positive significant to achievement performance. 3. Selling skills were positive significant to achievement performance. 4. Selling skills were found that play a part of mediating effect between training and assigned sales quota achieved. 5. Selling skills were found to have significant mediating effect between training and customer relationship operation. 6. Mutual effect between the product type and selling skills were positive significant to customer relationship operation. Those are some suggestions to the department stores, retailer, salespeople that have been working in this field; and also the directions were given in the future research in this study.