Abstract: Circuit-level simulation-based fault injection is cumbersome and time consuming in characterizing the soft error sensitivity.In order to overcome this difficulty,this paper presents a new technique to automate the whole injection process.LL(k) syntax analysis technique was employed to automatically parse the Spice netlist to extract fault injection targets' data;the netlist were automatically flattened by program to resolve the problem that single fault cannot be injected into multiple instantiated sub-circuits;by traversing the flattened netlist,we can inject current sources that represent soft errors into the netlist automatically.Additionally,a circuit level soft error injector HSECT-SPI was developed and fault injection experiments were carried out on ISCAS'85 and ISCAS'89 benchmark circuits.The experimental results show that our technique is appropriate to analyze the soft error sensitivity of cell and module circuits and to direct the design of high reliability integrated circuits.