Abstract: Electronic information industry belongs to typical high-tech industry and it develops quite fast all over the world in recent years. Electronic information industry is the pillar of Taiwan’s economy and is of vital importance to the Asia and even the whole world. Along with the deepening of opening-up and the development of economy of Mainland China, the investment from Taiwan’s electronic information industry to Mainland China is undergoing great changes. This research takes Taiwanese investment of electronic information industry as an example and studies its investment situation and location selection in investing Mainland China. The investment from Taiwan to Main China’s electronic information industry started from 1990s and experienced three periods: slow increase period (1991-2001), fast increase period (2002-2011) and steady adjustment (from 2001 up to now). The investment location showed a tendency of diffusion and gradually expanded from southeastern coast to inland Central and Western China. The investment transferred from manufacturing department to selling and researching departments. Based on the panel data of Taiwan’s investment to Mainland China’s electronic information industry from 2003 to 2014, this article analyzed the influence of the factors such as economy level, geographical agglomeration, and location cost on investment decision. Empirical studies firstly suggest that agglomeration effect is the most important factor that affects investment and its influence is increasing continuously. Taiwanese businessmen prefer those areas with large exterior market and solid Taiwanese investment foundation. Meanwhile, for overcoming the disadvantage of being non-native, Taiwanese businessmen tend to invest areas with more Taiwan investment. However, along with the familiarization of investment environment, this tendency is gradually becoming narrower. Secondly, the influence of location cost is gradually increasing. The shortage of labor and the increase of cost make the investors pay more attention to the issue of cost, and they try to transfer the highly standardized manufacturing process to inland areas with low labor cost. Environmental regulation makes the cost of controlling pollution grow and thus this has a negative influence on investment attraction. Thirdly, The technology level of the city has some influence on investment decision at a certain stage, but the influence is decreasing because of the gradual improvement of standardized production and there has been no significant influence since 2011.