Purpose: The purpose of this study was to provide an appropriate direction for effective field practice program by analyzing the influencing factors on satisfaction of field instructor in ambulance ride practice of paramedic students in Korea. Methods: The questionnaires were filled out by 204 paramedic students from July 22 to September 13, 2013. The collected data were analyzed with SPSS WIN 19.0 program. Results: The stepwise multiple regression analysis revealed that the most powerful predictor of satisfaction of field instructor was sincerity of directions. A combination of sincerity of directions (38.2%), achievement(15.4%), improvement of knowledge(3.9%) 4-week field practice(3.0%), 2 week field practice(1.6%), 4 grade(1.8%) pre-expectation of field practice(1.8%) accounted for 65.6% of the variance in paramedic students. Conclusion: We proposed the effective field practice program as well as sincerity of directions of field instructors. It is necessary to discuss before ambulance ride practice within the faculty and the field instructors.