Abstract: The dynamic simulation software is used to establish dynamic models of full-load and no-load transportation system of LNG tank truck. And the dynamic change trend of operation pressure, operation temperature and liquid level are studied during LNG tank truck transportation. The analysis shows that the pressure of LNG tank truck in full-load long-distance transportation is increased slowly, and it is not easy to cause overpressure relieving of tank safety valve. However the pressure of storage tank in no-load increased faster than the pressure in full-load. In addition, the minimal maintaining 5% of the LNG truck tank liquid level is reasonable to keep truck tank in the cold state.