In designing low Earth orbit (LEO) space-based radar (SBR) constellation systems, evaluating operational effectiveness based on constellation configuration is a critical prerequisite for system design and optimization. To assess the capability of detecting airborne moving targets, a comprehensive evaluation framework has been established, integrating detection and tracking performance while emphasizing the relationship between coverage and detection efficiency. This framework incorporates four key performance indicators: maximum revisit time, minimum detection time, average coverage duration, and coverage percentage. By developing a dynamic coverage stability model and a quantitative radar detection probability model, this study constructed an evaluation index system tailored to SBR constellations. Applied to the Walker- \(\delta \) constellation, the system explored various configuration schemes by adjusting three parameters: the number of orbital planes, the number of satellites per orbital plane, and phase factor. Utilizing the System Tool Kit (STK), simulated scenarios for aircraft target detection were developed across three representative aviation routes, followed by a performance assessment. The results demonstrated that an optimal balance between coverage, detection accuracy, and timeliness can be achieved within specified cost constraints. This research integrated the dynamic coverage and detection model, constructed a comprehensive evaluation index system, and realized the cost-benefit-aware optimization of SBR constellation through scenario-driven validation based on practical aviation routes, which has valuable engineering implications for the demonstration and development of SBR constellation systems.