Abstract The purpose of this study was to investigate the job behavior of preschool teachers , emphasizing the job satisfaction , job stress and professional effectiveness. Questionnaires on job satisfaction , job stress and professional effectiveness were sent out to 350 preschool teachers of Taipei areas and 225 of them responded to. The replying rate was 64.2% . The data was analyzed by chi-square test, t test and Pearson's product-moment correlation. The main findings of this study were: 1. The rate of intention to turnover of the preschool teacher was very high (46%) , especially those who taught in the private kindergartens. 2. There were significant differences in job satisfaction and job stress between public preschool teachers and private preschool teachers. Teachers who were in the public kindergartens earned higher score than teachers who were in the private ones. 3. The scores of professional effectivenes between public preschool teachers and private preschool teachers were no differences. 4. There were significant differences in job satisfaction, job stress and professional effectiveness between teachers who were no intention to leave and teachers who have intention to leave. The scores of the formmer were higher than the latter. 5. There were high correlation between job satisfation and professional effectiveness. 6. Most of the teachers showed a high intention to have oppertunity for inservice training.