The invention relates to a power grid engineering project category cost comparative analysis method based on a data analysis technology. Compared with the prior art, the problem that it is difficult to make a comparative analysis of the cost data of many power grid categories is solved. The method comprises the following steps: constructing a production technological transformation engineering project total cost list model; constructing a total cost bill-of-quantities library; constructing a bill-of-quantities reference library of a to-be-analyzed engineering project file; and carrying out category cost comparative analysis, converting the total cost of the bill of quantities into specific category costs through a project category conversion method, and carrying out comparative analysis based on the category costs. After a total cost list library is constructed through a bill-of-quantities cost allocation method, a bill of quantities similar to that of a to-be-analyzed project is extracted from all historical engineering projects, and a total cost list reference project model library is constructed to analyze the category costs of a to-be-analyzed project and a reference project.