The invention discloses an isomer scheduling method in a mimicry DNS defense system control unit. The method comprises the following steps: 1) obtaining a difference value between isomers according toparameters, the parameters comprising the number (L) of redundant executors, the minimum number (P) of scheduled executors, the type of an operating system of the isomers, and the type and version ofsource DNS analysis software adopted by the isomers; 2) obtaining credible values of the isomer according to the running state and the performance index of the isomer, wherein the credible values comprise a CPU utilization rate, a memory utilization rate, response time delay, running duration, an analysis success rate and scheduling participation times; 3) randomly selecting a seed random quantity; and step 4) finally selecting a group of isomers as a scheduling strategy according to the step 1), the step 2) and the step 3). By adopting the weighted random dissimilatory maximum algorithm introduced by the invention, the selection of the isomer is more scientific and accurate, the method is suitable for daily operation of the mimicry DNS defense system, and the operation of the mimicry DNSdefense system is promoted to be more stable and safer.