The invention discloses an excrement detector which comprises a base, a portal frame component, an automatic material supply component, a sample conveying system, a chuck component, a suction disk component, a first liquid feeding device, a second liquid feeding device, a first photographing device, a second photographing device, an identification and recording system, an electrical control system and upper-layer human-machine interaction application software. Under deployment of the control system, the excrement detector is in combined work, so that automatic pushing, sampling, coating, microscopic photographing, occult blood reaction photographing and automatic recycling of a sample are fully automatically implemented; and furthermore, the upper-layer human-machine interaction application software supplies a detection result. The invention also provides an excrement detection method. The excrement detector disclosed by the invention is high in automation degree; manual operation is not needed in a detection process; and cross infection among the samples can be avoided under automatic detection, and the problem that the detection result cannot be matched with a patient can be well solved.