The invention relates to a medicament for preventing and controlling plant virus diseases, which comprises the following active ingredients in portion by weight: moroxydine hydrochloride 4.0-97.0, oligosaccharins 0.05-20.0 and soluble filler 2.0-96.0. The medicament for preventing and controlling the plant virus diseases of the invention uses the synergistic action of the moroxydine hydrochloride serving as an antiviral medicament and the oligosaccharins serving as a resistance-inducing agent to prevent and control the occurrence and development of crop virus diseases, has preventing and controlling functions, can achieve excellent preventing and controlling effect when used alone before or after the onset of the diseases and is long in medicament adaptation period, small in dosage and low in cost.