Abstract: The detection of cement setting time is time-consuming and cumbersome to operate. Traditional manual detection methods are no longer able to meet the needs of large-scale detection. Replacing manual detection with automated equipment has become a major trend in the current development of the engineering detection industry. In this paper, the working principle of an automatic measuring instrument for cement setting time is introduced in detail. The accuracy and uncertainty of the measurement results were analyzed. The results showed that the relative extended uncertainty of the measuring result is 1.53%, which well proved high accuracy and stability of this instrument in practical applications.