A method of noninvasively detecting plant pathogenic virus and an electronic apparatus thereof are provided. The method is adapted to the electronic apparatus for detecting pathogenic virus in plants. The method includes the following steps. An excitation light beam is projected to the plant, and a reaction light emitted by the plant in response to the excitation light is received. An analytic optical spectrum corresponding to the reaction light is obtained, and whether the plant has the pathogenic virus or not is determined according to the analytic optical spectrum.
