The present invention relates to the technical field of herbicide crystallization process, particularly to Crystalline form C of shuangzuocaotong, and a preparation method therefor and use thereof. The Crystalline form C of shuangzuocaotong has an X-ray powder diffraction pattern having characteristic absorption peaks at the following 2θ positions: 10.159, 10.658, 13.318, 14.579, 16.096, 18.061, 19.322, 19.68, 20.04, 20.659, 21.281, 23, 24.16, 24.619, 26.101, 26.74, 30.359, 31.018, 32.378, 35.398 and 38.26 degrees, wherein 2θ has an error range within ±0.2°. The Crystalline form C of shuangzuocaotong has good stability, and its compounded composition with additional active ingredient(s) has a good control effect to broadleaf weeds and some gramineous weeds in wheat, significantly better than that of Crystalline form A of shuangzuocaotong.
