Abstract: Aimed at the problem that software written in Java is easy to be pirated by reverse engineering, a tamper-proof method at the Java virtual machine level is proposed. The encrypted bytecode file was restored by dynamic decryption before execution. Considering the key security issues of traditional cryptographic algorithms, white box ciphers were selected as encryption and decryption algorithms, and the logic of table import and export was modified for the defects of white box cipher tables, so that this solution could achieve a higher security level. Experiments have proved that it can more effectively prevent source code tampering without affecting the original functions of the software.