Abstract: Abstract: The production of the machine, which classifies small-sized fruits according to their images, depends on the speed of the image classification and the actuator. The existing classifier for fresh jujube has the issue that the efficiency of image processing doesn’t match the timeliness of executive mechanism. And the speed of the actuator and the accuracy of positioning restrict the efficiency of classification. In order to improve the speed of classification of the image classifier for fresh jujube, an image classifier for fresh jujube is designed based on electromagnetic synchronous executor in this paper. The machine is composed of roller conveyor chain, dialing plate chain, electromagnets, synchronous drive sprocket, STM32F407 image processor and STM32F103 co-processor. The dialing plate chain of the actuator consists of 60 unit dialing plates. Chain transmission was adopted to ensure the synchronous precision with the roller conveyor chain. The dialing plate tension spring was buckled by the switch of the buckle. The material of the buckle was silicon steel, of which the hysteresis loop was narrow, which can enhance the sensitivity of electromagnetic triggering, and made the dialing action finished instantly. The location of fresh jujube corresponding to the unit plate, which would guarantee the alignment accuracy between the head of the dialing plates and fresh jujube. Pop-up strength of the unit dialing plate was designed according to the peel hardness, the size and the weight of jujube. In image processing, G channel component, Sobel operator filtering, Otsu binaryzation, and eigenvalues extracted by ellipse fitting were adopted. A threshold value was used to calculate the percentage of the color of green, extract the size of feature value of the color and classify the image of green jujube. The algorithm was suitable for fast processing embedded system. The theory of algorithms and the test of image classification show that the synchronization error of chain transmission was 0.413 mm, the pop-up force of unit dial plate was 2.57 N, which was less than the damage strength (12.69 N) of the peel of red jujube, the time of each image processing was 50 ms, the time of the actuator for acting was 40 ms, the speed of roller conveying was 320 mm/s, the speed of classifying was 20 jujubes per second, the accuracy rate of classification was 93.7%, the intact rate was 100%, and the maximum capacity was 1 400 kg/h. Results indicated that the sensitive trigger and the synchronous mechanism of synchronous electromagnet ensured the classification precision, and the touch force of dial plate was less than the damage stress of the red jujube skin. Also, the hardware design of image processing was an embedded system, which met the requirements of fast calculation through the algorithm of image processing and feature extraction. The running effect of the prototype achieves the purpose of fast, accurate and nondestructive classification.