Abstract: In order to solve the problem of large volume of L, LCL filters for shearer traction and limited ability to suppress high-frequency harmonics near the switching frequency of rectifier, based on the analysis of the structure and filtering characteristics of L, LCL, LLCL filters, the element volume and loss are added as limiting conditions, and the relationship between inductance ratio, damping resistance and current attenuation coefficient, resonant frequency, damping loss is analyzed, A parameter design scheme of a special LLCL filter for the rectifier side of the traction frequency converter of underground shearer is proposed. By using simulation test and actual test, it is determined that LLCL filter can improve the high-frequency harmonic suppression characteristics, reduce the harmonic distortion rate of feedback current, reduce the harmonic impact on the power grid, and further reduce the filter volume and loss; Compared with the traditional design method, the designed total inductance and loss are lower, and the working cost is saved.