The invention provides a darkroom type security inspection device and a method for inspection through the security inspection device. The darkroom type security inspection device comprises a shell forming a closed darkroom and a part in the shell. The part in the shell comprises a sampling system and a sample processing system. The sampling system comprises a conveying device, an X-ray detection device for detecting the position of a detected object and a sample collecting device for collecting a sample. The X-ray detection device is used for determining that the detected object reaches the corresponding position in the sampling system, so that the X-ray detection device and the conveying device convey the detected object to the expected position together. The sampling system, the sampling processing system and a sample detection system are communicated through connecting pieces. The security inspection device can conveniently, rapidly and effectively conduct sampling and detection, a package is not opened, the to-be-detected object is not damaged, and the darkroom type security inspection device and the method are suitable for rapid screening and detection of forbidden objects in airports, customs and the like.