Abstract: The hazards and protection of penetrant testing in limited space are often ignored. In order to reduce the hazards, security issues of penetrant testing are introduced. The reasons of hazard in the limited space penetrant testing was put forward, and wrong habits in site were pointed out. After inhaled or contracted with the penetrant testing agent by the eye or the skin, the human’s respiratory system, eyes, skin and central nervous system were hurt seriously. To minmize the hazard, the methods of better management, ventilation, and gas detection, labor protection were put forward.