提出了时序电路的部分扫描法可测性设计中扫描链的构造方法，包括扫描链的选取、扫描链的排序、多链扫描设计三部分内容。采用组合等效电路的方法求测试向量，并用实例进行了验证。模拟结果表明，选取２０％～４０％的触发器至扫描链，用较少的测试向量，可达到很理想的故障覆盖率，测试时间依赖于触发器在扫描链中的顺序以及扫描链的个数 The construction method of the scan chain in the design of testability of the partial scan method of the sequential circuit is proposed, which includes the selection of the scan chain, the sequencing of the scan chain and the design of the multi-chain scan. The test vector is obtained by the method of combining equivalent circuits and verified with examples. The simulation results show that 20% ~ 40% of the flip-flops can be selected to scan the chain with less test vectors, and the ideal fault coverage can be achieved. The test time depends on the order of the flip-flops in the scan chains and the number of scan chains number