A pressure and liquid level sensing system for a tank container or tank vehicle comprising a vessel for containing a liquid substance, such as Liquified Natural Gas (LNG), etc. The pressure and liquid level sensing system comprises a pressure sensor for measuring a gas pressure inside the vessel and a liquid level sensor for measuring a liquid level inside the vessel, the pressure sensor and the liquid level sensor comprises a first and a second pressure sensitive elements and a first and a second printed circuit boards respectively. A circuit on the first printed circuit board converts a pressure signal into an electric signal, a circuit on the second printed circuit board converts pressure signals of a gas-phase space and a liquid-phase space into electric signals of 4-20 mA or 0-10V standard. In this way, the pressure and the liquid level can be accurately measured. Furthermore, the measured values are digitalized, such that both driver and remote control center can know variation conditions of the pressure and the liquid level of the transported medium in real time, thereby transportation safety is improved.