The invention relates to a parallel computing network division method capable of absorbing interface delays of different step lengths. The method comprises the following steps: step 1: determining a transmission line port equation of a Thevenin equivalent circuit incorporating into a sub-network; step 2: performing different step length simulation of transmission line decoupling; step 3: performing preset simulation step length discretization on a sub-network I and a sub-network II; and step 4: simulating the discretized simulation step length. The method can realize complete parallel simulation and is an ideal simulation method in real-time simulation. A transmission line suitable for network division in a network needs to be found by applying a different step length simulation algorithm based on the transmission line and is transformed into a transmission line model of a big step length delay, and the network is decoupled through the model. A computing error caused by no interface delays during electromagnetic transient parallel network division of different step lengths can be realized and numerical oscillations and simulation errors caused by the interface delays can be reduced or avoided.