Concolic testing is a novel technique in automatic software testing. It systematically achieves higher coverage by combining concrete and symbolic execution. Some previous works have implemented testing tools based on the excellent idea. But it still meets some difficult on real code testing. The interaction with the running environment is one of them. In this paper, we try to deal with the file operations in the source code. With the support of file handling, we can enhance the ability of testing tools and improve the testing precision.