Abstract: Because of the short range of α particle, the conventional α activity direct measurement method cannot detect α radioactivity of irregular surface and pipe in a large area. Long-range α detector(LRAD) is currently applied for the detection of α radioactive contamination in these areas and becomes one of the effective means of measurement of α radioactive contamination. LRAD is widely used in these environments, in which α radioactivity is difficult to measure at close range such as potholes, nuclear facility plumbing. The basic principles, development, research status, application prospect and development direction of LRAD were described in this paper.