Partial evaluation plays an important role in many areas such as program optimization and automatic software generation. This paper applies partial evaluation to validating compilers. The design of peC, which is a subset of C, and the formalized description of partial evaluation strategy for peC are presented. Furthermore, the implementation of a partial evaluator for peC, and a compiler testing framework based on partial evaluation are provided. Experiments show that this new approach can not only detect errors which can be detected by other methods in GCC and LLVM but also found some errors which are not detected by the other methods. In summary, the work by this paper demonstrates applying partial evaluation in testing compilers is effective.