Abstract: Objective To explore the possibility of sensing detection of thymidine kinase(TK) in sera as a clinical diagnostic indicator of tumor. Methods To detect the TK levels of different tumor serum samples by using amplified mass piezoelectric quartz crystal immunosensors. Results Liver cancer sera have the highest TK level(2.44±0.46 ng/mL),the galactophore sera take second place(1.16±0.24 ng/mL),and the TK levels of both cancer sera are distinctly different from that of the other malignant tumors(P<0.001).The TK levels of lung cancer sera, digestive system cancer sera, Genital system cancer sera and other malignant tumor sera are closely consistent and there is no distinct difference among them ( P > 0. 05), but there are distinctly different f rom that of the carcinoid sera ( P < 0. 001) . Moreover, the TK level of carcinoid sera is distinctly higher than that of normal human sera ( P < 0. 001) . Conclusion 　The amplified mass piezoelect ric quartz crystal immunosensors as a new sensitive quantitative method for TK in human sera has great potential for the clinical diagnosis of cancers and the distinguish of cancer types, especially for the clinic diagnoses of liver cancer and galactophore.