Micro earth pressure sensors are often used to measure the earth pressure within a soil mass or the earth pressure acting upon the boundaries of buried structures in centrifuge model tests. As pressure is a contact measurement, disturbances to the soil become inevitable when the sensors are embedded in it; these disturbances affect the soil stress distribution and promote artificial boundary conditions or soil arching. Considering this problem, calibrating each sensor is necessary before the test is conducted and measurements are made. Traditional calibration methods using solution or gas as the calibration medium cannot accurately reflect working conditions. Thus, in this work, a system designed to calibrate micro earth pressure sensors for centrifuge model tests is proposed. Multiple sensors are calibrated in the laboratory considering two working conditions:with a rigid backrest and without the backrest. Water, silty clay, or Fujian standard sand are used as the calibration media. Calibration coefficients are then obtained to establish the relationship between output voltage and earth pressure. The results show that the loading and unloading segments are relatively linear when the calibration medium is water; when the medium is sand or silty clay, however, highly non-linear behavior and large hysteresis are noted. The hysteresis ratio R is defined to evaluate the hysteresis quality, and computed results indicate that the calibration media and sensor types are the two major factors affecting valves of R. A number of factors that may affect the calibration results of the sensors are then discussed. The material properties and geometric characteristics of the sensors, the preparation of the foundation soil, changes in soil compactness and soil strength due to preloading and cyclic calibration, the calibration medium, and the working state were found to exert the most significant influences on the calibration coefficients. Therefore, to enable correct measurement of earth pressure, the calibration conditions, especially the calibration media and the working state, must be as similar as possible to the test conditions, and all sensors should be calibrated individually.