Abstract: The degree of diagnosability is an important standard to measure the reliability of the interconnection network.The Cross-cube is a variant of the hypercube，whose natures are superior to the hypercube.The PMC model is a classical diagnostic model，which has two famous diagnosis strategies：precise strategy and pessimistic strategy.It is proved that the degree of diagnosability of n-dimensional Cross-cube is [n+1(n≥4)] under the precise strategy and [2n-2(n≥4)] under the pessimistic strategy.Thus，it proves that the degree of diagnosability of the Cross-cube is greater than that of the hypercube under the precise diagnosis strategy，and the same as that of hypercube under the pessimistic strategy.

Key words: parallel computing system, interconnection network, diagnosability, PMC diagnostic model, Cross-cube

摘要： 可诊断性度是衡量一个互连网络可靠性的重要指标。Cross-cube是超立方体的一种重要变型，与超立方体相比有许多好的性质。PMC模型是并行计算系统中的一种经典的诊断模型，在该模型下有两个著名的诊断策略：精确策略和悲观策略。证明了n维Cross-cube在精确策略下的可诊断性度是[n+1(n≥4)]，在悲观策略下的可诊断性度是[2n-2(n≥4)]。证明了Cross-cube在精确策略下的可诊断性度大于超立方体的可诊断性度，在悲观策略下的可诊断性度与超立方体的可诊断性度相同。

关键词: 并行计算系统, 互连网络, 可诊断性, PMC诊断模型, Cross-cube