The security analysis of Security Protocol Implementations(SPI) is an important part of cybersecurity. However, with the strength of property protection and the widely used applications of code obfuscation technology, the previous security analysis method based on SPI is hard to carry out. Therefore, under the condition that SPI is not available, this paper analyzes the security of the SPI using the unpurified security protocol traces and security protocol implementation ontology. First, we construct the implementation ontology to describes the attributes of the ontology terms. Second, the format analysis method is presented based on unpurified flow. Third, the mapping method is proposed to build the mapping between the security protocol trace and the implementation ontology. Fourth, a is presented to analyze the security of SPI. Finally, FSIA software is designed and implemented according to the method we proposed to analyze the login module of a university information system, the result shows that there is a risk of Ticket leakage in the login module. Compared to the previous method,our proposed method can deal with unpurified network traces and find the vulnerabilities of network and system.INDEX TERMS Security protocol implementation, network trace, security protocol implementation ontology, format analysis, semantic analysis.