With the urbanization development, municipal road reconstruction project gets increasingly common and how to scientifically and effectively use the survey data in the planning period and save the cost become the focus of engineering survey. Based on the analysis on the geotechnical engineering elements of site topography and geological structure, stratum and hydrogeological conditions, rock and soil physical and mechanical properties, the stability evaluation and seismic effect and geotechnical engineering evaluation, by the comparison of the above key elements, the timeliness of the survey data is discussed to determine survey point arrangement, exploration depth and the work load of sampling and in-situ test. Take the specific project as an example, the paper discusses the key points of investigation, and points out that for survey data in planning period, the formation variation within the depth of 4.0m should be mainly considered and the focus should be on broken roads.