The invention relates to a detection method of the CPU utilization of a router in the technical field of network communication. The method comprises the following steps: constructing a virtual network on a computer A, configuring the network parameters of a virtual router and a router to be detected; installing a Vtune performance analyzer on the router to be detected, separately connecting the router to be detected and the computer A to a switch B, connecting the bridge C of the virtual router connected with the router in the virtual network with the host interface of the computer A; starting the Vtune performance analyzer on the router, sending the messages of the virtual network to the router; and closing the Vtune performance analyzer after a time t, and directly reading the name, calling time and CPU utilization of each function of the router to be detected on the Vtune performance analyzer. The testing environment of the invention is easy to realize, network topology and configuration can be flexibly changed; under the premise of not reducing the testing accuracy, the testing complexity is lowered, the operation is easy, the resources and testing time are saved, and the testing cost is reduced.