The invention provides an offshore oilfield grid study state method including special large-scale motor start analysis, start and shutdown unit or load-adjusted system power flow distribution analysis and optimal power flow study-state single/multiple step implementation verification analysis, and aims to analysis the effect on system by actual motor starting actually and discrete the starting process of the motor into different static sections to simulate the dynamic motor starting process. The analysis is more accurate, the power vacancy is shared by multiple balancing machines determined by the system, the actual situation is met more accurately through dynamic power flow analysis, the system state can be represented more accurately, an operator can grasp the effect on system by operation previously so as to adjust the actual grid operation more leisurely, and the working environment can be optimized for the operator.