Due to the high electromechanical coupling coefficient, scale effect and no strict requirements on the working temperature, the flexoelectric materials are expected to be used for sensors, actuators, structural health monitoring, etc. Based on the barium strontium titanate(BST) micro cantilever beam structure, the dependence of driving frequency on the transverse flexoelectric coefficient was analyzed, and scale effect was discussed. The transverse flexoelectric coefficient was obtained by using the low frequency vibration of the piezoelectric micro actuator. The results show that flexoelectric materials present obvious scale effect in the aspect of sensing and the sensing property will be superior to piezoelectric materials when the thickness of the beam decreases to micro or nano scale.