Biodegradable hyperbranched. polyglycerols (dHPGs) were synthesized through oxyanionic initiating hybrid polymerization of glycerol and glycidyl methacrylate. Due to the introduction of ester linkages into the hyperbranched polyglycerol backbone, dHPGs showed good biodegradability. and low, cytotoxicity. Benefiting from the existence of terminal hydroxyls and methacryloyl groups, both the anticancer drug methotrexate (MTX) and fluorescent, probe Rhodamine-123 could be conjugated onto, the surface of dHPGs easily. The resultant MTX-conjugated. polymers (dHPG-MTXs) exhibited an amphiphilic character, resulting in the formation of micelles in an aqueous solution. The release of MTX from micelles was significantly faster at mildly acidic pH of 5.0 compared to physiological pH of 7.4. dHpG-MTX micelles could be efficiently internalized by cancer tells. MTT assay against cancer cells showed dHPG-MTXs micelles had high anticancer efficacy. On the basis of their good biodegradability and row. cytotoxicity dHPGs provide an opportunity, to design excellent drug deliver systems.