A light surface imaging laser radar based on a line light source (1) and an area-array camera (4), and a detection method. The radar comprises a line light source (1), a lens (3), an area-array camera (4), and a calculation and analysis unit (5), wherein the plane illuminated by the line source (1), the plane of the lens (3) and the plane of the area-array camera (4) intersect on one line; when the line source (1) illuminates an obstacle on the plane, the light is reflected by the obstacle; the reflected light is imaged at a corresponding position of the area-array camera (4) through the lens (3); the shape of the image is a contour of the obstacle illuminated by the line source (1); and the position of a corresponding object is calculated according to the position of the image. This is equivalent to multi-point simultaneous parallel detection, so that an obstacle and an aerosol molecule, etc. appearing on an object surface can be imaged, and position and contour information about all illuminated objects is instantly calculated, and can be applied to various environments such as ranging and spatial detection.