The lava tubes on the Moon, Mars, and other extraterrestrial bodies have the advantages of radiation resistance, meteorite impact resistance, lunar/Martian dust protection, and great thermal insulation. Constructing a habitat base in the lunar or Martian lava tube is one of the feasible options for humans to stay in extraterrestrial bodies for a long time in the future. This paper investigates the feasibility of the lava tube sealing technology, which is one of the most basic technical problems in the construction of lava bases. The space seal structures and the rapid leak detection technique are discussed. Two lava tube sealing schemes are proposed. One is based on the independent and flexible gasbag, and the other is based on the coating treatment for the inner lava tube surface. The key technical problems that need to be solved are described. The development trend of the sealing technology is discussed, and future research in this field is suggested. This study will provide technical support the future deep space exploration and base construction in extraterrestrial objects.’