This paper intends to examine the relationship among managerial philosophies of a peace culture, in-service training and labor management relations. There are no specific clarifications or answers available from existing literature; hence, this study aims to clarify the relationship among these three variables. A total of 207 questionnaires were issued to the Taiwanese branches of the multinational enterprises headquartered in the US, Japan, and Taiwan. The research findings indicate that there is a significant and positive correlation between managerial philosophies of a peace culture and in-service training. There is a positive correlation between in-service training and labor management relations. There is a significant and positive correlation between managerial philosophies of a peace culture and labor management relations. Also, managerial philosophies of a peace culture and labor management relations are subject to the mediating/influence of the in-service training. General-education training, supervisors or employee does not improve labor management relations; ethics-education training, supervisors and employees have a high degree of identity in the US and Japan, and Taiwanese supervisors in charge of two of them have no confidence; world public education training, US-Japan supervisors in charge of high degree of identity are very important, only in Taiwanese supervisors there is a lack of confidence. In the 21st century, the development of in-service training in MNE attaches great importance to ethics-education training and world public education training to be able to improve the performance of MNE.