The invention relates to a substrate processing system, which comprises a substrate processing device and a substrate detection device. The substrate processing device comprises a vacuum chamber. The substrate processing device is used for processing a substrate in the vacuum chamber. The substrate detection device comprises an image sensor and a control module. The image sensor is arranged in the vacuum chamber, and the image sensor is used for detecting and feeding back the state of the substrate. The control module is connected with the image sensor and the substrate processing device and is used for controlling the operation of the image sensor and controlling the operation of the substrate processing device according to the feedback state of the substrate. The invention further provides a substrate detection method. The substrate detection method comprises the following steps of detecting the state of the substrate; judging whether the substrate is a defective substrate or not; on the condition that the substrate is judged to be a defective substrate, sending a defective substrate signal; sending out an instruction according to the defective substrate signal; receiving the instruction and executing the corresponding operation. According to the system and the method, a defective substrate that is processed in the vacuum chamber can be timely found out. Therefore, the unnecessary waste and the unnecessary loss can be avoided just in time.