The major aim of this study is to investigate when a firm want to improve employees' job satisfaction and organizational commitment, it is better to put more effort on selecting the applicants whom share the right personality, or put more resource on job design that can get higher return. Findings indicate that enhancing organizational management and job design have stronger effect on job satisfaction and organizational commitment than the impact of selecting workers whom share higher internal control and achievement motivation, in addition, among the approaches of job design, job enrichment (feedback and autonomy ) has stronger effect than that of job enlargement (integrity and variety ).