Abstract: There were many methods of classification for surrounding rock of highway tunnel nowadays.The results from any individual method could be assumed as an estimation of the practical situation.Combining these methods by a definite algorithm could enhance the advantages and overcome the disadvantages inherited in them,and the information of the surrounding rock could be used sufficiently in classification as well.Based on the above thought,and considering the situation that the parameters of surrounding rock and the classification standard were stated in the form of interval numbers,a new interval numbers-based integrated classification method for surrounding rock of highway tunnel was proposed.In order to reduce the information loss in calculation process,a new definition of distance between the two interval numbers was given.And a combined algorithm with addition and multiplication was selected as the classification function which could take functionality and coordination of the employed methods into account.By using the function,the value of classification index was calculated.The subject was classified corresponding to the minimum value of classification index.A practical highway tunnel with two typical sections was taken as an example.Firstly,three classification methods,i.e.,rock quality designation system ROD,rock basic quality system BQ and wave velocity vp of the rock were employed to classify the surrounding rock individually.Then the proposed method was used to get the final value classification index.The method was recommended for its clear modeling,tangible physical significance and simple calculations.It was shown that the proposed method was concise,stable and practical.