In this study we attempted to analyze the change of protein and mycelial activity during low temperature storage progressed. At first, esterase and peroxidase isozymes were detected at third and fourth subculture in Pleurotus ostreatus and peroxidase isozymes in Pleurotus eryngii were detected at first and second subculture but esterase isozymes showed almost same band patterns subculture advanced. The decolorization ratio of media color including indicator were decreased according to subculture advanced in P. ostreatus and P. eryngii. However there were not significantly difference of mycelial growth, fruit body yield, esterase isozyme band pattern and laccase activity of P. eryngii according to storage periods at low temperature. Therefore, it was possible to store sawdust spawn of P. eryngii at 4℃ for 120days.