The multi-stage adsorption chillers can be driven by low temperature heat source under 70℃. The purpose of the study is to clarify the maximum specific cooling capacity (SCC) of the multi-stage adsorption chillers by the cycle time optimization. The optimal cycle times of the multi-stage adsorption chillers were found using the particle swarm optimization. The comparison of the optimal performances revealed that the two-stage adsorption chiller was superior to the single-stage and three-stage adsorption chillers within a wide temperature range of the driving heat source.