When histograms are used for data processing, it is possible to find distribution rules of the data and examine the data quality. This paper presents the drawing procedures of histograms and deals with the application of histograms, taking as a case study the test results of the rocks obtained during the engineering geological survey for the Guitang River Bridge on the Changsha Huoxing Road. The application shows that when histograms are used in survey, it is possible to evaluate the rationality of the layering and examine the quality of the samples based on the statistics of the test data.