Abstract: The decision tree classification algorithm C4.5 is the most popular and classical classification algorithm in the data mining. But, there are some defects in it, the processing of continuous variables in the C4.5 algorithm consumes too much time, according to this characteristic, the paper improves the processing of continuous variables to enhance the efficiency of the algorithm. The improved algorithm has better efficiency and has the same accuracy comparing with the C4.5 algorithm when building decision tree. 

Key words: data mining, decision tree, C4.5 algorithm, continuous variables