Embodiments of the present invention disclose a method and an apparatus for calling a critical resource service. The method in the embodiments of the present invention comprises: receiving call request information of the nth process, wherein the call request information comprises identification information of the critical resource service and identification information of the critical resource; by obtaining the call information of the critical resource service, obtaining the identification information of the critical resource called by the valid process; determining whether the identification information of the critical resource in the call request information is the same as the identification information of the critical resource called by the valid process; and if so, blocking the nth process. In the embodiments of the present invention, according to whether the identification information of the critical resource in the call request information is the same as the identification information of the critical resource called by the valid process, whether the nth process is blocked is determined, so that the processes corresponding to the different critical resources still have the opportunity to call the critical resource service, and efficiency of calling the critical resource service is greatly improved.