Abstract: Control code obfuscation is intended to prevent malicious reverse engineering of software by masking the program control flow. But the file size and execution time often increase intensively. Because the opaque predicate is difficult to resist the dynamic attacks, the article put forward to make use of "garbage code" to carry out the control flow confusion. The branch garbage code and circulation the garbage code are used in the method and a hash function is introduced here to control the number of insert operation. Our experiments show that aided with the method, obfuscation is done efficiently with moderate increases in code size, execution times, while making the obfuscated code resilient to a variety of reverse engineering attacks.