The first theoretically exact spiral cone-beam CT reconstruction algorithm developed was by Katsevich [1- 2]. Recently, Yu et al. [3-4] implemented the algorithm numerically. Although the method is very promising, the computation is very intensive. It requires huge amount of computer time. Recently, people [5-6] began to parallelize the algorithm for achieving high performance computation. This paper presents an analysis of data decomposition and data communication in the parallel Katsevich algorithm [5] and develops an analysis expression to evaluate the performance of the algorithm parallelism. The results based on the analytical model and numerical benchmarks compared in a fare agreement. The analytical model provides a great tool to evaluate high performance computing benchmarks in the parallel Katsevich algorithms.