The study of search and graphical display of hazardous blocks on roadway roofs is of great importance to the safe excavation and long-term utility of roadways. In this paper, the GeneralBlock program was used to carry out preliminary analyses of blocks, which were developed based on the General block method. Following this, the removability and stability of the buried and fixed blocks under engineering disturbances were analysed according to the minimum fixed area of the blocks. In addition, accurate positioning and three-dimensional graphical displays of hazardous blocks were carried out through the coupling of GeneralBlock and 3DMine. Finally, a technology for searching and displaying hazardous blocks on roadway roofs in underground mines was developed, and it was subsequently applied to the production roadway in #92 ore body and the development roadway in Zinc polymetallic ore body of the Tongkeng mine, Guangxi, China. One hundred and twenty hazardous blocks were found on the test site during the production process of #92 ore body. These blocks were mainly located in the segments of 0–3 m and 12–20 m on the Y-axis; a total of 31 hazardous blocks were found in the development roadways of the levels 255 and 305 in Zinc polymetallic ore body, and the volume of the largest hazardous block located in the B5 roadway was 1.44 m3.