In this paper, we propose a cooperative load balancing scheme focusing on improving effective resource utilization and mitigate the co-channel interference across domains through fair resource allocation in heterogeneous network (Het-Net). We models the load balancing issue as an optimization problem for minimizing the effective resource utilization. Simulation results have demonstrated that the system effective resource utilization is significantly reduced through our proposed inter-domain load balancing scheme. It is also demonstrated that by incorporating the co-channel interference in the optimization process, the proposed scheme has great advantages in interference management of Het-Net.