This paper proposes a DC parallel-series topology structure for offshore wind farm based on the VSC-HVDC technology. It uses permanent magnetic synchronous generator wind turbines with simplified structure, which has the advantage of DC boost, decreasing the required offshore platform construction that the substation and converter station needed, reducing the losses occurred during commutation and transformer process, reducing the complexity of the system, construction costs and being conducive to system maintenance. Also, this structure to some extent solves the problems of system fluctuations and branch circulation caused by wind turbine faults in DC series system and DC series-parallel system. Therefore, this paper presents a coordinated control strategy for DC parallel-series structure. Finally, the stability of this structure and effectiveness of the control strategy are validated through the software simulation experiments.