Abstract: We have tested the swelling ratio and swelling pressure of the load direction(overhead direction)of Chengdu clay intact specimen with pure water.And have tested the free swelling ratio using remodeling specimen.We have discussed the expansive level of Chengdu clay based on results of 6 groups of samples,at the same time we have researched into unlimited lateral expansion characteristic through the experiments on load lateral(overhead direction)swelling of Chengdu clay.This paper summarizes the common engineering geologic disasters of Chengdu clay and gives advices on engineering treatment measures.