Abstract: The key questions of the study on the rule of modification of trusts are: who, under which circumstances, have the right or power of modifying or terminating trusts. Under American law, after the creation of trusts, the settler, the beneficiary and the court have the right or power of modifying trusts under specific circumstances. However, the rule of modification of trusts changes from the tradition rule of the priority of the settler's intentions to the modern rule of considering the beneficiary's interests. China should learn something useful from this change to make our rule of modification of trusts perfect.