In this paper, a fundamental frequency of 13 MHz and a thickness-increased n-m-type electrode are adopted to improve the frequency response of a quartz crystal microbalance (QCM) to blood coagulation. The thrombin time (TT) and viscosity of standard plasma were measured with this specially designed QCM at different reaction temperatures, and the results were compared with those of a commercial coagulometer and capillary viscometer. The results showed that the frequency shift caused by blood coagulation is greatly enhanced and more than twice that of a traditional QCM. Also, a higher reaction temperature not only accelerates the coagulation reaction but also weakens the frequency response. A comparison between the plasma viscosity measured with the QCM and that measured with the capillary viscometer shows that the QCM can measure plasma viscosity well on the basis of the theory of the liquid attenuation layer. Our research indicates that QCM-based coagulation measurement can not only measure the coagulation time but also the plasma viscosity, which is meaningful for related fields.