The invention discloses a device and a method for automatically detecting and sorting light emitting diodes (LEDs). The system comprises a first conveying device which is used for loading materials onto LED material strips and conveying the LED material strips and is capable of dotting unqualified LED material strips, a detecting device which is used for detecting the surface appearance, the size, the color and defects of each LED bracket in the LED material strips, a second conveying device which is used for sending out the detected LED material strips, a sorting device which is used for storing out the unqualified LED material strips, a display device which is used for displaying detection data, and a control device which is used for comparing the detection data with standard data to determine whether the LED brackets are qualified or not, and controlling the whole process of material loading, detection, dotting, conveying and sorting of each device. The method comprises multiple steps of standard setting, control device startup, sampling, comparison and output. Products can be automatically classified, the automation degree is high and the labor force is effectively reduced.