Abstract: To evaluate the biological property and safety limitation of a specific sentinel lymphoscintigraphy imaging agent，⁹⁹Tc^m-rituximab，⁹⁹Tc^m-rituximab were analyzed for chemical and radiochemical purity, via SDS-PAGE and ITLC-SG. The immunoreactivity were detected via ELISA and flow cytometry. The safety limitation and biodistribution were tested according to the Chinese Pharmacopeia. The results showed that ⁹⁹Tc^m-rituximab, with a labeling yield of 90%~95%, was intact, and processed similar immunoreactivity of rituximab. The final product was bacteria and pyogen free, and was safe to the body. According to the data of biodistribution, most of agent was excreted by the kiney, and the radio uptake decreased from (14.01±0.61)%ID/g at 1 h to (3.51±0.48)%ID/g at 24 h. The liver also uptook the agent. No accumulation was found in the normal tissue. ⁹⁹Tc^m-rituximab is stable and contains a good immunoreacivity and can be effectively used for clinical study.