The invention relates to a preparation method for a pesticide suspending agent, and belongs to the field of preparation of pesticide additives. The preparation method comprises firstly baking air-dried acer palmatum pulp to be dry, wrapping with tung oil tree leaf, immersing in a mixed solution of polyacrylamide, octadecy trimethyl ammonium bromide and sulfuric acid, filtering and collecting the filtration matter; and performing distillation on the collected filtration matter and theophylline, collecting the fraction, and finally mixing the fraction with tebufenozide, sodium dodecyl benzene sulfonate and sorbitol. The beneficial effects comprise that the prepared pesticide suspending agent is uneasy to thicken and cake, uneasy to decompose, good in safety aiming at crops, and applicable to multiple crops, is capable of fully giving play to pesticide efficiency, is relatively low in toxicity, small in environmental pollution and easily-available in raw materials, and possesses extremely high economic value.