The utility model relates to a scraper knife angle modulation device of a bulldozer, which is mounted between a scraper knife and a segmental support of the bulldozer and comprises a pin boss A, a pin A, a connecting rod, a plurality of expansion washers, a pin B and a pin boss B, wherein the pin boss A is fixed on the scrapper knife; one end of the connecting rod is connected with the pin boss A through the pin A, the other end thereof sequentially penetrates through a hole formed in the segmental support and the expansion washers and is connected with the pin boss B through the pin B; the pin boss B is fixed on the segmental support through a bolt. The scraper knife angle modulation device of the bulldozer, disclosed by the utility model, is convenient to dismantle and mount, simple in structure and long in service life, can be dismantled for many times according to the specific demand, and avoids the problem that the angle is difficult to regulate because the bolt is not used for a long time and is rusted.