Since National Health Insurance program formally went into effect in March 1995 in Taiwan, the residents enjoy high quality but relatively cheaper medical care compared with the most developed countries. To manage a hospital successfully, the important goals are to attract and then retain as many patients as possible by meeting potential demands of various kinds of the patients. This study first conducted the survey based on SERVQUAL model to identify seven major criteria from patients’ or their families’ viewpoints at Show Chwan Memorial Hospital in Changhua City, Taiwan. When the key criteria were found, the second survey developed for applying decision-making trial and evaluation laboratory (DEMATEL) method was issued to the hospital management by evaluating the importance of criteria and constructing the causal relations among the criteria. The results show that trusted medical staff with professional competence of health care is the most important criterion and mutually affects service personnel with good communication skills, service personnel with immediate problem-solving abilities, detailed description of the patient’s condition by the medical doctor, and medical staff with professional abilities. Therefore, trainings on communication skills and problem-solving abilities would result in positive interaction for patients to trust medical staff. When the trusted medical staff provides professional competence of health care to patients, satisfaction would be increased.