The characteristic of the superconducting magnetic energy storage(SMES) system is faster response, longer life time, more economical, and environment friendly than other uninterruptible power supply(UPS) using battery. So, the SMES system can be used to develop methods for improving power quality where a short interruption of power could lead to a long and costly shutdown. Recently, cryogen free SMES has developed using BSCCO(Bismuth Strontium Calcium Copper Oxide) wire. We fabricated and tested the conduction cooling system for the 600 kJ class HTS SMES. The experiment was accomplished for the simulation coils. The simulation coils were made of aluminium, it is equivalent to thermal mass of 600 kJ HTS SMES coil. The coil is cooled with two GM coolers through the copper conduction bar. In this paper, we report that the test results of cool-down and heat loads characteristics of the simulation coils. The developed conduction cooling system adapted to 600 kJ HTS SMES system and cope with the unexpected sudden heat impact, too.