Being used for drug modification, the multi-arm single molecular weight polyethylene glycol and an active derivative thereof provided herein can effectively improve the solubility, stability, and immunogenicity of the drugs, improve the absorption of the drugs in vivo, prolong the half-life of the drugs, and increase bioavailability, enhance efficacy, and reduce toxic and side effects of the drugs. A gel formed from the active derivative of the multi-arm single molecular weight polyethylene glycol provided herein can be used for the preparation of controlled release drugs so as to prolong the action time of the drugs, thereby reducing the number of administrations and improving patient compliance.
