The invention discloses a laser radar road reconstruction and expansion exploratory survey design method. The method comprises the steps of A designing a result coordinate benchmark, measuring basic control and measuring pavement control points; B determining parameters including the data density, acquisition route and the like, and acquiring vehicle laser radar data along a main road and a ramp; C determining parameters including the data density, flight design and the like, and acquiring airborne laser radar data according to a designed flight strip; D realizing laser radar data fusion by refining laser point cloud plane coordinates and elevation coordinates and refining track line data; E acquiring characteristics of road traffic lane lines by using point cloud intensity information, and realizing extraction of characteristic lines of road pavements, protection and the like by adopting a method of projecting three-dimensional point clouds to a two-dimensional plane; F recovering planar elements and longitudinal surface elements of an existing road; G producing a DEM (digital elevation model), a DOM (digital orthophoto map) and a DLG (digital line graphic); H collaboratively designing laser radar measurement and road reconstruction and expansion CAD (computer-aided design), designing flat, longitudinal and transverse cross sections of a road, comparing and selecting schemes, and outputting final design drawings and charts.