Energy-saving thermal insulation system in building outer wall

The invention relates to the technical field of building heat preservation, and discloses a building outer wall internal energy-saving heat preservation system which comprises a first heat preservation plate and a second heat preservation plate located behind the first heat preservation plate, a partition plate is installed between the first heat preservation plate and the second heat preservation plate, and a first damp-proof plate is installed behind the partition plate. A second moisture-proof plate is mounted behind the first moisture-proof plate; an air inlet mechanism is arranged at the edge of the left side in the partition plate; the connecting mechanism is arranged, the connecting base in the connecting mechanism is located between the first moisture-proof plate and the second moisture-proof plate, a gap is formed between the first moisture-proof plate and the second moisture-proof plate, water drops generated during moisture regaining are prevented from permeating the first heat preservation plate,