We consider the channel allocation problem for the low earth orbit (LEO) satellite systems. This problem is known to be NP-complete and a couple of heuristic algorithms have been developed. In this paper, we convert the problem into a simpler from through the concept of pattern. And we suggest another algorithm based on Simulated Annealing for this simplified problem. The results of perfomance comparison show that our method works very well. Simulation results are reported.