在状态转移规则的基础上，局部更新规则和全局更新的蚁群算法的规则，我们提出一个IM证明蚂蚁的最低成本的服务质量蚁群算法（QoS）的路径用于解决网络路由问题与延迟以及背包约束中进行模拟。约52.33％蚂蚁找到成功的QoS路由。并收敛到最佳。-based on the state transition rule，the local updating rule and the global updating rule of ant colony algorithm ，we propose an im proved ant colony algorithm of the least cost quality of service(QoS)unicast routing．The algorithm is used for solving the routing problem with delay．delay jitter．bandwidth，and packet lOSS constrained． In the simulation，about 52．33　ants find the Successful QoS routing ．and converge to the best． It is proved that the algorithm is efficient and effective．