The coefficient of earth pressure at rest ( K0 ), which is affected by a number of factors, is an important parameter for the design and construction of geotechnical engineering. Choosing appropriate method of test and analysis is the key to ensure the reliability of the test results. To investigate the K0 characteristics of a overconsolidated silty clay stratum in Harbin City, a series of in-situ tests, including K0 stepped blade test(KSB), dilatometer test(DMT), and pressuremeter test(PMT) together with laboratory K0 oedometer test were conducted and comparatively analyzed. The results showed that KSB avoided soil disturbance and empirical problems of conventional push-in tests, and possessed the virtues of simplicity, efficiency and high precision. The value of K0 obtained from KSB was in the range of 0.45-1.81, and presented a decreasing trend with the increase in depth. On the other hand, the K0 values from laboratory K0 oedometer test and PMT were severely underestimated due to the fact that the released initial lateral stress in the unloading process cannot fully recover during the reloading process. The reliability of DMT was strongly dependent on the empirical analysis formula selected. It is found that the K0 values of Harbin soil were markedly overpredicted by the conventional Marchetti formula; however, it underestimated the soils in Shanghai, Suzhou, Hangzhou and Xi’an. To estimate K0 of Harbin overconsolidated silty clay, a novel empirical formula was proposed based on the calibration of Marchetti formula, which can provide some reference for the related survey and design.