The invention relates to a device and a method for detecting stored-grain insects, which consists of a stored-grain insect separation part, a stored-grain insect transmission part and a machine vision part, wherein the stored-grain insect separation part efficiently separates stored-grain insects from a grain sample by utilizing a screening motor to drive a vibrating screen; the stored-grain insect transmission part can transmit an acquisition box to an appointed position and can automatically clear screen underflows in the acquisition box; the machine vision part consists of a control module, a computer, a lighting box, a near infrared camera, a visible light CCD, a light source and corresponding software. The method for detecting stored-grain insects comprises the following steps of sequentially acquiring near infrared images and visible light images of the screen underflows for information fusion, extracting entire morphological characteristics and local morphological characteristics of the stored-grain insects, and automatically determining the kinds and the quantity of the live stored-grain insects by utilizing an optimized stored-grain insects characteristic space and identification software, thus realizing the real-time, precise and automatic detection of normal stored-grain insects.