The invention aims to provide a method for detecting a tomato aspermy virus (TAV). The method utilizes loop-mediated isothermal amplification (LAMP) to detect the tomato aspermy virus (TAV). The method comprises the steps of preparation of a reaction system, incubation treatment, inactivation treatment and product detection in turn, wherein the reaction system comprises 0.5 to 1.5 mol/L of Betaine, 2 to 25 mmol/L of dNTP, 2 to 15 mmol/L of Mg<2+>, an outer primer and an inner primer, and the concentration ratio of the inner primer to the outer primer is 1:1-1:8. The method has the advantages that the method does not need a special instrument (such as a PCR instrument), and is quicker and more economic than the prior laboratory method; and the method is simple and convenient to identify, has high specificity, can judge whether a target fragment is amplified or not by observing with the naked eye or detecting the turbidity of deposit through a turbidity meter and an ultraviolet imaging system, so as to judge whether a sample plant to be detected is infected with the tomato aspermy virus or not, and does not need to use a gel electrophoresis method for observation.