Wireless sensor networks are already employed in numerous applications including military, industry, and health. Among the several inherent limitations in wireless sensor network, security is a critical concern. The declared security functions of wireless devices should be well verified. In this study, a security testing method based on security levels is proposed for wireless sensor networks. In addition, an experimental security testing platform for WIA-PA-based wireless sensor networks is implemented. The test results show that the platform is a feasible platform for assessing device security levels in wireless sensor networks.