The invention discloses an automatic detection device for the quality of an injection molding product, and the device sequentially comprises a sampling chamber, a stretching chamber, a combustion chamber, a bending chamber and an impact chamber from the left side to the right side. The interior of the sampling chamber is provided with a first guide rod, a second guide rod, a sliding plate, a firstspring, a sampling groove, a gap, a sampling rod, a sampling head, an inner pipe, an outer pipe, and a second spring. The device is reasonable and simple in structure, is low in production cost, is convenient in installation, can achieve the sequential detection of the stretching performance, frame resistance, bending performance and impact performance after the sampling of the product, directlyobtains the data, and avoids the repeated detection so as to iron out the defects in the background technology. In the detection process, the device can achieve the synchronous detection of the quality data of different types of products, thereby greatly improving the efficiency. The processing of the parts of the device is not complex, and the parts can be directly purchased, thereby greatly reducing the production cost. Therefore, the device is suitable for the large-scale popularization.