Abstract
Abstract The purpose of this study is to explore the difference of employee engagement under merger and acquisition of Pfizer company. The research results indicate that： 1. Under M&A, well preparation in advance and comprehensive communication plan will increase employee engagement level. 2. Under M&A, the talent deployment and management is the most important success factor. 3. Under M&A, organization restructuring will benefit people development and increase employee engagement level. 4. Under M&A, for ensuring every colleague in the new company move forward to the same goals, the enterprise has to build a new vision and mission. Keywords： Merger & Acquisition, Employee engagement, Organization restructuring, People development