As one of the typical emerging markets, China's 3rd generation (3G) mobile communications service is proliferating rapidly recently, and great potentialities are expected in the market. Thus the strategy to improve the share in the emerging 3G service market appears to be an important topic for the mobile communications operators. To study the topic, the authors apply an agent-based model to study the interactions among the individuals and the complex externalities in China's 3G mobile communications market, and analyze several strategies of the operators with computational simulation. Based on the analysis, the efficient strategies for each operator to improve the market share are proposed. Furthermore, the analysis also shows that how the efficiency of the strategies varies depending on the different market environments. Because the emerging markets share some common characteristics, the conclusions can also be applied in other emerging communications markets.