The invention provides a road comprehensive detection method and a system based on a line structured light and a geological radar. According to the invention, the synchronous detection of a road pavement and a roadbed is realized, compared with a condition that the road information acquired by the road detection method in prior art is single, the method and system provided by the invention can acquire comprehensive road 3D information and roadbed information. The method comprises the steps: a line structured light 3D measuring technology and a geological radar are combined by the method to apply on road detection; the road detection is realized through the line structured light 3D measurement, and the obtained is used for constructing a road 3D model; the geological radar detects shallow-layer geological structure, and roadbed radar data information is obtained. The road pavement 3D model and radar image information are combined to construct a comprehensive road information model at last. The system is formed by a roadbed detection module, a pavement detection module, a trigger detection and distance measurement module, a vehicle body movement information detection module, a data acquisition module, a data processing and road model generating module, the modules work coordinately, and the method is realized.