The invention discloses a frozen liquefied gas tank container vacuum-pumping system and method. Through an inner tank body heating module and an interlayer hot nitrogen circulation heating module, continuous circulation heating is conducted, then nitrogen replacement is conducted, an inner barrel circulation heating system works continuously, then two or more rough vacuum-pumping units are used for rough vacuum pumping, after the vacuum degree reaches 0.5 Pa, nitrogen replacement is completed three times, and after rough vacuum pumping reaches about 1 Pa, fine vacuum pumping is conducted; andafter the vacuum degree is pumped to 10<-2> Pa, internal circulation heating is stopped, meanwhile, the vacuum degree is sealed for cooling, and then the vacuum degree is detected. The interlayer hotnitrogen circulation heating module is introduced, the interlayer space can be directly heated in the circulation process, most of moisture and small solid particles which are easily brought out are brought out through circulation while the interlayer space is rapidly heated, the vacuum pumping speed is increased in principle, energy consumption needed by the vacuum pumping procedure is reduced, and the vacuum pumping efficiency is improved, so that the cost of the whole production process is reduced, and carbon dioxide emission is reduced.