Hydrogen-rich gas from fertilizer plants and ethylene plants can be sent to refinery in a petrochemical complex. It can alleviate the deficit of hydrogen in refinery. Thus the optimization of inter-plant hydrogen network in petrochemical complex is important. A superstructure of inter-plant hydrogen network with purification reuse is constructed. The corresponding mathematical model with the total annualized cost as objective function is proposed and the commercial optimization software GAMS is utilized to solve the problem with DICOPT as a solver. The hydrogen network of a petrochemical park is optimized. The results shows that the total annual cost can be reduced by 33.1% comparing to the current hydrogen network.