In heterogeneous network, it is likely that many mobile users send access requests at the same time. To avoid network congestion and provide users with good service experience, a novel joint group call admission control (JGCAC) algorithm is proposed. This algorithm includes two procedures: Firstly, the number of users allocated to each network is determined according to load balancing policy. Secondly, based on the evaluation values about network conditions and user requests, suitable users are admitted to each network by extended Hungary Algorithm. Simulation results indicate that the proposed algorithm can maintain load balancing among networks, reduce dropping rate and achieve a better user satisfaction.