Resource allocation is one of the key problems in radar network. A modified particle swarm optimisation (PSO) algorithm is presented here to improve the performance of resource allocation in radar network with large baseline, where multiple tasks with multiple parameters were considered. First, the resource allocation mathematic model for radar network with large baseline was established. Second, based on modified PSO, the resource allocation algorithm is presented and it can simultaneously deal with both discrete and continuous variables. Finally, the simulation experiment is presented to verify the proposed algorithm. The simulation result suggested that the proposed algorithm is feasible and can satisfy the requirement of resource allocation in the radar network.