The Ant Colony Algorithm (ACO) can be applied to cluster scheduling better, but its traditional pheromone update method brings the performance matching and load balancing and so on, which affects the performance of cluster scheduling. In order to solve these problems, an Improved ACO (IACO) is put forward. The pheromone is adjusted more reasonably by adjusting the performance matching factor and the load balancing factor. It is observed that the processing time is shortened, the CPU utilization is improved, and the performance of the cluster is improved effectively.