Delay time is an important technical indicator of trailing cone system. In order to accurately predict the pipeline delay time of trailing cone system, a theoretical model of the trailing cone system was established based on the continuity equation and the momentum conservation equation with the influence of viscous resistance in pipelines under different flow states taken into consideration at the same time. The applicability of the model was improved and the accuracy of the model was verified by experiments, which makes the model applicable to practical engineering use. Moreover, the influence of the pipeline structural parameters and environmental parameters on the time delay of the trailing cone system was studied. The results show that the pipeline delay time increases with the increase of pipeline length and environmental pressure, and decreases with the increase of pipeline diameter, step pressure and environmental temperature.