Previous literatures have studied the relationship between business ethics and staff morale. However, little research examined such a relationship among Multi-National Enterprise. Moreover, by reasoning, cross-cultural management system may have a moderating effect on that relationship. Therefore, the purpose of this study is to investigate the relationship of business ethics and cross-cultural management system to staff morale. The data was composed of high-ranking managers of the subsidiary companies of British, U.S. and Japan in Taiwan. All 368 recovered survey questionnaires, the questionnaire efficiency was 38.73%, where the valid questionnaires were 331. Our empirical results indicated that the carry out of business ethics in enterprises was positively related to staff morale and also supported was the finding of the moderating effect of cross-cultural management on the relationship between business ethics and staff morale, an approach endorsed within ethics literature. The findings indicated that organizational leaders could integrate business ethics and the cross-cultural management system as a means to generate a favorable work environment which enhanced staff morale.