Objective To establish a rat model of post-traumatic stress disorder (PTSD) through single-prolonged stress (SPS) and to observe the effect of social isolation on the behavior of the SPS model rats. Methods A total of 36 rats were randomly divided into the normal group, SPS model group and SPS combined with social isolation group. The rats in both SPS model group and SPS combined with social isolation group were modeled by single-prolonged stress, and the rats in the SPS combined with social isolation group were raised separately after modelling. The weight gaining, the total movement distance in open field test, the frequency of grid crossing, the single maximum movement distance, and the freezing frequency and time durations in the freezing behavior test were measured after 7 days of modeling. Results Compared with the normal group, the weight gaining and the single maximum movement distance of the rats in the SPS model group were significantly decreased ( P < 0.01), as well as the total movement distance and the frequency of grid crossing ( P < 0.05), while the freezing frequency and time in the freezing behavior test were significantly increased ( P < 0.01). Compared with the normal group, the weight gaining and crossing times of the rats in the SPS combined with social isolation group was decreased ( P <0.05), and the freezing frequency and time durations in the freezing behavior test were increased ( P < 0.05). In addition, compared with the SPS model group, the total movement distance in the open field test, the frequency of grid crossing and the single maximum movement distance of the rats in the SPS combined with social isolation group were increased ( P < 0.05). Conclusions The rat model of post-traumatic stress disorder is successfully established by single-prolonged stress, and 7 days of social isolation may alleviate the anxiety state of SPS model rats.