To solve the technical problem of long-term monitoring of shear modulus of highway embankment base layer, based on the piezoceramic material bender element, design shear wave generated and received devices applied to the Shangri-La to Lijiang highway embankment base layer on the horizontal direction. A series of tests were conducted with sandy gravel soil whose gradation conforms to the highway G-A-4 gradation to optimize the design of steel frame dimensions and mesh cover of the bender element sensor. The results indicate: (1) The steel frame width does not have a significant effect on the received signal amplitude or p-wave transmission, and the final design of the steel frame width is 0.3 meter on the consideration of frame stiffness. (2) The steel frame length has a significant effect on the received signal amplitude, and the optimal design of the steel frame length is 1.2 meter. (3) By comparing six different mesh cover materials, stainless steel mesh is selected as the mesh cover material taking its excellent durability properties and relatively less influence on the received signal amplitude into consideration. (4) Because of the press-hard characteristic of the sandy gravel soil, an increase of confining pressure would increase the shear modulus of the soil. In the experiment, the bender element shows an increase in the shear wave velocity, which indicates that bender element is suitable for quantification of aggregate base layer stiffness. The research results provide a new method for quantitatively describing the stiffness of embankment base layer.