Provided is a use of plant crude extracts from Pueraria peduncularis for preparation of pesticides against pomacea canaliculata and oncomelania snails, the method of extracting crude extracts from Pueraria peduncularis comprising the steps of: (1) drying the roots of Pueraria peduncularis at 50°C and grinding the dried roots of Pueraria peduncularis into crude pieces of a size ranging from 1 mm-5 mm (2) using ether petroleum and chloroform as extraction solvents to extract the crude pieces obtained in step (1) in a sequential order, the weight ratio of the crude pieces to the extraction solvents being 1:3, and subsequently using methanol, 1-butanol, ethanol or isopropyl alcohol, or a combination thereof, as an extraction solvent to carry out the extraction at 40-70°C for 12-24 hours three times and concentrating and drying the extracted liquid to obtain a concentrate, namely crude extracts of Pueraria peduncularis.
