Abstract: Guangcong fault zone and Carboniferous strata are distributed in Baiyun District of Guangzhou, and Guangcong fault zone exists in some Carboniferous strata. The Carboniferous strata have the lithologic conditions of karst, while the fault zone provides the geological process of karst, which makes the karst engineering geological conditions in this area extremely complex. As an important economic development area in Guangzhou, Baiyun District has many construction projects. Therefore, it is necessary to conduct in-depth study on its geological conditions to provide geological reference and ensure the safety and smooth progress of construction projects. Based on hundreds of engineering survey projects in Baiyun District, combined with Guangzhou geological map and fault structure map, this paper studies the key engineering geological characteristics of Carboniferous strata in Guangcong fault zone in Baiyun District by means of collection, sorting and statistical analysis. The specific method is as follows: the deepest rock surface and the largest karst cave exposed by drilling are divided into three groups according to the depth of rock surface and the height of karst cave, and the range of the depth of the deepest rock surface and the height of the largest karst cave at each location in Baiyun District is visually reflected by marking on the geological map. At the same time, according to the spatial location of Guangcong fault zone, Carboniferous strata and engineering survey projects, it is divided into three kinds of distribution relations, namely, engineering survey projects are only distributed in Carboniferous strata, engineering survey projects are only distributed near Guangcong fault zone, and engineering survey projects are distributed in Carboniferous strata of Guangcong fault zone. The results show that the deep weathering trough and karst cave near the fault zone are often more developed in the Carboniferous strata. The distribution and trend of weathered deep troughs and karst caves are basically consistent with the spatial position of Carboniferous strata in Guangcong fault zone. The karst engineering geological characteristics of Carboniferous strata in fault zone are complex, which will lead to many uncertainties in geotechnical engineering investigation. Therefore, when conducting geotechnical engineering investigation, targeted measures should be taken according to the engineering needs and investigation purposes. For example, we should adopt a fine survey plan, combine a variety of exploration technologies, strengthen the test and data analysis, and dynamically adjust the survey strategy.