Background: This study aims to analyze the behavioral changes of healthcare providers and influencing factors after the reviewer unification of auto insurance medical benefit claims by an independent review agency. Methods: The comparison data were collected from the second half of 2013 and the same period of 2014. The key indicators are the number of admission days, the number of outpatient visits, inpatient ratio, inpatient medical expenses, and outpatient medical expenses. Results: Four indicators (number of admission days, number of outpatient visits, inpatient ratio, and outpatient medical expenses) showed statistically significant drops, while one indicator (inpatient medical expenses) showed no significant change. Conclusion: The reviewer unification of auto insurance medical benefit claims by an independent review agency showed significant reduction in cost and patient days.