The invention provides a capacitive contact-type displacement measurement sensor and sensing system. The sensor comprises a fixed part and a moving part. The fixed part comprises a fixed insulation substrate and a capacitance electrode piece group fixed on the fixed insulation substrate, wherein the capacitance electrode piece group comprises conductive electrode pieces and fixed side thin film covering each conductive electrode piece. The moving part comprises a moving insulation substrate and a grounding electrode piece group located on the moving insulation substrate, wherein the grounding electrode piece group comprises conductive electrode pieces and moving side thin film covering each conductive electrode piece; the fixed part and the moving part are arranged to be opposite each other in a Z direction perpendicular to an X direction and the moving part and the fixed part are in contact-type sliding fit connection in the X direction so that the moving side thin film and the fixed side thin film can maintain zero clearance in the Z direction; the capacitance electrode piece group and the grounding electrode piece group can form a variable capacitor in a moving process. The sensor has the advantage that there is no need to perform compensation design for clearance changes, so that the structure can be simplified and the performance of the sensor can be improved.