Wireless audio transmission has always been the focus of Bluetooth application scenarios. Future audio use cases, such as multi-streaming to assist stereo imaging experiences, broadcast audio sharing, hearing aid support, etc., have higher requirements for quality of service (QoS). LE Audio based on Bluetooth Low Energy (BLE) is considered to be a replacement for the Bluetooth classic audio standard in the next generation of audio applications. However, until now, the performance of CIS-based LE Audio has not been fully analyzed. In this paper, we propose a mathematical model to evaluate the performance of CIS such as packet loss rate (PLR), throughput, backlog, delay, and average power consumption. In addition, the feasibility of multi-hop transmission based on CIS is explored, and the model is extended to analyze the end-to-end PLR and throughput. Finally, the accuracy of the proposed model is verified by simulation results, and the relationship between CIS parameters and performance is analyzed, providing guidance for parameter selection in LE Audio applications.