This research investigated the relationship between the service quality, hospital image, medical behavior and the royalty of the patients treated in a regional hospital in Taiwan. It took hospital image and medical behavior as the intermediated factors. The results showed significant correlation between the service quality, medical behavior and the royalty as well as the service quality had the direct influence toward the royalty. The service quality can also take the hospital image and the medical behavior as the intermediated factors to effect the royalty. As a result, the hospital should work hard to raise the service quality in order to enhance the royalty of the patients.