Abstract: The grade of complex degree of geological environment is traditionally evaluated by the way of qualitative analysis or empirical method, so the evaluation result is always influenced by the excessive factor of subjectivity.But the extenics evaluating method is derived from extenics, which can establish a synthetical evaluating model with many performance parameters and indexes.Extenics evaluating can show the result quantificationally.The extenics evaluating method can make the evaluating indicators optimally summarize the practical geological situation, which can effectively avoid the influence caused by the factor of subjectivity, therefore the evaluating achievements have higher reliability naturally.Compared with previous empirical method the extenics evaluated results can basically reflect the actual grade of complex degree of geological environment, as well as the extenics evaluating method can be effectively used to settle the actual engineering problems.Therefore the extenics evaluating method is of great application prospect, the results may be served as reference for modification and compilation of related standards and codes.