The cluster technology brings a new solution for the WEB service, the key point is load balancing strategy. Based on the existing algorithms, a content-classification load balancing algorithm is proposed. By using content classification, user requests could evenly distribute to the nodes in the cluster, so that each node would get roughly the same amount of various types of requests. To prevent the load skew, a feedback mechanism was introduced, furthermore, the weight of each node interval was adjusted by using an equivalent load-alternant and would multiplicative decrease in critical area. The test shows this algorithm could improve the performance of the cluster system.