Abstract: In order to study the rational compensation standard of ecological benefit for public welfare forests and to maintain its operational motivating force,the authors calculated the amount of financial compensation for ecological benefit of public welfare forests by adopting the method of forest assets assessment as well as the method of transferring principal to interest according to measurement standard of compensation for value loss.The results were as followings:1) if government purchasing the public welfare forests operated by collective and individual for once,it will cost ￥22 billion to compensate the operators of public welfare forests;2) if the property rights of public welfare forests do not change while it continues to be operated by its owners according to project specifications,government compensation will account ￥0.722 billion annually to the present operators in order to ensure its normal ecological benefit.Standard compensation per year for different tree species of public welfare are as follows:Chinese fir ￥236.0/hm²,Masson pine ￥214.4,broadleaved forests ￥219.1,eucalypt ￥195.4,bamboo grove ￥87.4 and shrubbery ￥39.1.Public welfare forests with typical characteristics of external economics should be equalized by reasonable amount of compensation to its operators and thus maintain its operation motive force.