With the widespread adoption of SOA in large-scaled distributed systems, Service-Based Software system has brought much attention in the field of software engineering. Capable of monitoring system status and dynamically adjusting accordingly, Adaptive Service-Based Software system enhances SBS with self-adaptive ability to satisfy the system requirements in aspects of QoS, etc. This paper defines the structural description of ASBS, proposes a performance evaluation model based on reflective Petri net, and introduces the constructing and analyzing approaches for the performance model, which also incorporates explorations in ASBS performance analysis.