In the evaluation of information security level, the vulnerability of the target system can be found through the penetration technique and the security problems found in the grade evaluation are verified by the penetration technology. The methods and tools of penetration test are introduced. The application of the penetration test tool in the evaluation of security level of the information system is described in detail. The analysis indicates that the penetration test can further evaluate the system deeply, which can help to increase the completeness and accuracy of the level evaluation conclusion.