Macro-micro collaborative networking enables operators to achieve continuous deep coverage of networks at low cost. The low-power, small-sized, flexible and easy-to-deploy micro radio base station (mRBS) overcomes the constraints on site and transmission resources faced traditionally when macro base station (MBS) is deployed, which could well cover blind spots and blind areas of network coverage and improve the capacity of traffic hotspots under the premise of not introducing strong interference. It can better meet the ever-growing communication demand of user equipment (UE) and cater to the brand new service trend of cross mobility, residence and commercial markets. For the problem of inter-cell wireless resource management in macro-micro co-networking, this paper proposes a joint transmission and dynamic spectrum allocation strategy based on micro cell clustering in massive multiple input multiple output (MIMO) system. The strategy is implemented in two steps to optimize the network weighted sum rate. First, the proposed algorithm performs micro-cell clustering according to the current channel state information (CSI) of users, so as to reduce the inter-cell interference as much as possible and improve the system capacity. Then, the macro base station (MBS) and each micro-cell cluster dynamically allocate sub-carriers to its service users according to the current traffic request information to maximize the network weighted sum rate and improve the resource utilization. The simulation results shows that the proposed micro-cell clustering and dynamic spectrum allocation strategy can effectively improve the system throughput while reducing the interference among users in macro-micro collaborative networking.