Abstract: Objective To valuate the pharmacokinetics of cisplatin in enhancing the radiosensitivity of stageⅡa-Ⅱb bulky cervical cancer. Methods Thirty-six patients with stageⅡa-Ⅱb bulky cervical cancer were treated intravenously with cisplatin (30 mg/m2) and cisplatin levels were measured in tumor tissues and serum of the patients at the random time points of 1, 2, 4, 6, 10, 18, and 24 h following the injection. Cisplatin levels were also measured in the tissues following administration of different radiation doses by flameless atomic absorption spectrometry. Results Cisplatin level in the tumor tissues was the highest at 4 h following the injection, and its serum level showed obvious reduction within 2 h following the injection. Radiation increased cisplatin level in the tumor tissue. Conclusion Cisplatin level reaches the highest level in the cancer tissue at 4 h following intravenous injection, a time when cisplatin can best execute its effect in enhancing the radiosensitivity of cervical cancer, and cisplatin administration in later stage of radiotherapy may achieve better effect than early stage administration.