A call admission control method can ensure the admission rate of the high priority business, and simultaneously greatly improve the admission rate of the low priority business. The occupied bandwidth of currently admitted business flows of a WiMAX network is denoted by Σbi,max, a bandwidth threshold of a base station system is denoted by bth, a total bandwidth that the base station system can distribute to users is denoted by btotal, applied minimum and maximum bandwidths are denoted by bN+1,min,bN+1,max, respectively for a new arrival (N+1)th business flow. When Σbi,max+bN+1,max≦bth, the base station system will directly admit a request of an (N+1)th business flow. When Σbi,min+bN+1,min>btotal, the base station system will directly refuse the request of the (N+1)th business flow. When Σbi,max+bN+1,max≧bth and Σbi,min+bN+1,min≦btotal, comparing an admission rate P with a random number α to determine whether a new arrival (N+1)th business flow is admitted or not.