Polycrystalline silicon polishing solution and preparation method thereof

The invention relates to a polycrystalline silicon polishing solution and a preparation method thereof, the polycrystalline silicon polishing solution comprises the following raw materials by mass: 9.5-30 wt% of deionized water, 0.1-5 wt% of a guanidine compound, 0.1-5 wt% of a pH regulator, 59.5-80 wt% of silica sol, and 0.1-1 wt% of a bactericide; the total mass percentage content of the raw materials is 100%; the content of a single metal ion in the silica sol is 0.9 to 1.1 ppm. According to the polycrystalline silicon polishing solution and the preparation method thereof, the grinding material silica sol with relatively low single metal ion content and the additive without metal ions are introduced by matching the reasonable raw material ratio, and meanwhile, the cleanliness standard of a preparation environment is strictly controlled, so that the single metal ion content of the prepared polycrystalline silicon polishing solution is about 1ppm, and meanwhile, the polycrystalline silicon polishing solution