It is said that IC fabless companies are with the high-tech and high additional values and the employees are also with well-educated background. When the companies grow up, the scales increase and the products become more diversification, to induce the original working model maybe not suitable to use. It needs to slight modify the handling way base on the current situation and the merger and acquisitions business models are also generated at the same time. However, it needs to carefully survey and evaluate before the merger and acquisitions and to arrange the internal resources for integration after it. Due to these will be impacted to the success or failure for the acquisitions step. IC design houses in Silicon Valley are successful working for a long time and it includes many new companies and the cases of acquisitions. This research hopes to use the competitive five forces analysis, cluster theory and the market competitive structure analysis to know the marketing analysis after company B to merged the company C and its related competitive strength