The community structures of the weighted network of research areas(WNRA) are studied by using the theory of complex network.A weighted network of research areas is construted based on the proposals about Chinese natural science basic research.And then,a community structure detecting algorithm applied to weighted network is presented.The effect of the algorithm is proved by public experimental data.The numerical results indicate that the community structure of WNRA changes yearly.The work may shed some light on the status of the development about Chinese basic research and is helpful to adjust the classification system to reflect the real status more accurately.