Based upon the investigation and comparison of the forest conditions of the Greater Hing’an Range before and after the forest fire in 1987，this paper indicates that fire plays two roles to forest under human control：first，fire can burn out vast forest and the surrounding communities in a short time，which results in severe damage and lose；second，fire is an indispensable ecological factor of nature，playing an important role in sustention of ecological diversity.China should strictly comply with the contemporary ecological principle，make introspection of the current guideline for fire prevention，and transfer from traditional forest fire prevention to contemporary forest fire management.