The work aims to solve the problem that the vertical packaging machine cannot effectively detect and automatically reject the unqualified products with cigarette package missing. A detector based on photon detection was designed. Through the design of x-ray tube, high voltage power supply, X-ray detector, main control board, display screen, cigarette missing strip rejection mechanism, OPA354 and AMP02 reduced gain secondary amplification, gauss filter, detection shift program, etc., the unqualified products with cigarette package missing were fully detected and accurately rejected. The results showed that the detection rejection rate of the defective cigarette strips was ≥99.9% and the error rejection rate was ≤0.01% after the installation of the detector. The device can improve product quality, reduce material consumption, increase equipment operating rate, and reduce the risk of the package missing cigarette strip entering the next process. It can be widely used in all packaging equipment.