This study investigated compound nerve action potential (CNAP) changes of nerve trunk subjected to stretch at various strains and strain rates. An animal model of rapid stretch injury to nerve based on traffic accidents was developed in order to study CNAP changes of nerve trunk subjected to acute stretch. 18 bullfrogs were dissected and the sciatic nerves’ trunks were obtained. The nerve trunk was stretched by 6%, 12% or 18% of its length and the tensile strain rates were 30s-1 and 50s-1 respectively. The results showed that at 6% strain and 30s-1 strain rate, the amplitude, action potential duration and conduction velocity of CNAP had a slight change. When the strain and strain rate continued to be increased, the amplitude, conduction velocity and area under the curve would be decreased while the action potential duration would be increased. At 18% strain and 50s-1 strain rate, CNAP conduction was almost completely blocked. The different strains or strain rates had a significant effect on nerve signal conduction. Under the same strain, a higher strain rate would increase the probability of nerve conduction block. These findings are of great significance to study the injury mechanism of rapid nerve stretch and to evaluate the nerve functional damage level in traffic accidents.