Recently, because of the competitive environment, Taiwan's high-technology industries have undergone enormous change in a series of enterprise mergers and acquisitions. The enterprise mergers and acquisitions led us to study the e-business integration impact issues on continuous assurance. Our study found that the information technology integration strategies and assurance process integration methods had an impact on their continuous assurance performances and effectiveness. We used case study research methodology that including data collection, case attendant interview, data analysis and summary finding steps for creating new model applications of information technology integrations. The information technology integration assurance (ITIS) model steps include information technology infrastructure building, assurance process integrations, database immigration and analytic and alarm methods. Our findings close the literature theory gaps between IT integrations and continuous assurance; it will be applicable for information technology integration and continuous assurance about post-enterprise mergers and acquisitions.