The utility model provides a communication network topology suitable for gentle straight many level of modularization change of current valve, including a plurality of pulse boards, a plurality of receiving and dispatching optic fibre and a plurality of power unit, all contain a plurality of pulse board light mouth in every pulse board, a plurality of power unit fall into a plurality of power unitand organize, include two power unit at least in every power unit group, have at least a power unit to be connected with the pulse board via pulse board light mouth through receiving and dispatchingoptic fibre, still carry out the optic fibre interconnection between the power unit in the power unit group. The communication that has increased between the power unit is connected, and accessible optic fibre carries out the information interaction between messenger's unit. Make the communication network interconnection between power unit can be divided into a plurality of kinds on this basis, can satisfy high pressure and large capacity gentle straight many level of modularization change of current valve system have that the high reliability requires and change of current valve contains themore occasion requirement of power unit progression, save communications facilities, reduce the fault is rateed.