Provided is a deflection measurement assembly for concrete beams and plates. The deflection measurement assembly comprises a horizontally-arranged reference beam, the reference beam is sleeved by at least a displacement sensor fixing module, a central position of a column of a main body of the module is provided with a horizontal and through reference beam reserved hole, the reference beam penetrates through the reference beam reserved hole, one side wall of the column, parallel to the axis of the reference beam reserved hole, is provided with a vertical sensor limiting groove, the other wall surface parallel to the axis of the reference beam reserved hole is provided with vertical puller bolt reserved holes, and puller bolts are arranged in the puller bolt reserved holes. When the deflection measurement assembly is in use, a sensor is limited by the sensor limiting groove, the measurement can be performed as long as the displacement sensor fixing module and the sensor are simply tied, and a plurality of displacement sensor fixing modules corresponding to a plurality of sensors can be provided so that the measurement of the deflection at multiple positions can be performed. According to the deflection measurement assembly, the structure is simple, the operation is convenient, the cost is low, the positioning of the sensor is facilitated, the practicality is high, and the deflection measurement assembly is applicable to various displacement sensors with different shapes.