The invention discloses a water-washing and butyraldehyde-removal method for polyvinyl butyral resin. The method includes three processes, namely measurement of butyraldehyde content, addition of a butyraldehyde azeotrope, and removal of butyraldehyde and its azeotrope by water washing and heating. By adopting the method, the number of times of water washing can be reduced, water is saved, the residual amount of butyraldehyde is largely reduced, the weight of the butyraldehyde in a finished product can be controlled to be smaller than 0.001%, meanwhile the method can effectively remove other impurities and the quality of products is largely improved.