BACKGROUND Boanmycin hydrochloride, a new antitumor agent, has a short half-life and fast clearance speed in vivo. The aim of this research was to investigate the effectiveness of peritumor injection of boanmycin hydrochloride within temperature-sensitive gel in situ using Hep-G2 hepatoma nude mice model. METHODS Nude mice with human Hep-G2 tumor in right flank were randomly divided into four groups: normal saline group, in situ gel only group, boanmycin hydrochloride in situ saline group, and boanmycin hydrochloride in situ gel group, and were treated with injection of corresponding agents into peripheral tissue of the tumor. The volume of the tumor and the body weight of the mice were regularly measured, and tumor growth curve was generated. The size, internal echo, and blood flow of the tumors were observed by color Doppler ultrasonography. Histopathologic changes of the tumor after treatment were observed under both optical and transmission electron microscopy. RESULTS The tumor growth was significantly inhibited by peritumoral therapy in boanmycin hydrochloride in situ gel group with the tumor inhibitory rate of 86.76%. The blood flow of the tumor was still seen in both normal saline group and in situ gel only group on color Doppler ultrasound. Punctate calcification and dotted blood flow were seen in boanmycin hydrochloride group; however, there was massive calcification and no blood flow in the tumor in the boanmycin hydrochloride in situ gel group. Large areas of necrosis and apoptotic cells were shown by microscopic observation in boanmycin hydrochloride in situ gel group. CONCLUSION Temperature-sensitive boanmycin hydrochloride in situ gel can effectively delay the release of boanmycin hydrochloride and increase its anticancer effects for liver cancer in animal model.