Abstract: Aiming at the minimal makespan of job shop scheduling,a method named an improved"king strategy"for selecting crossover individuals is proposed in this paper.The improvement of crossover operator is selecting offspring based on father and son competition mechanism.Then these algorithms were operated in Matlab.A 10-jobs-and-10-machine JSP is given and the simulation results indicated the convergence rate and search precision of IKGA are remarkably better than the genetic algorithms based on"king strategy"for selecting crossover individuals.