The present invention relates to a manned submersible balancing and automatic longitudinal tilt adjustment device and adjustment method, comprising a pressure-resistant shell in which a plurality of seats for passengers are installed, a
pressure sensor is installed on the bottom of each seat, and the
pressure sensor detects the weight of the passengers on the seats, and a
ballast water tank is provided one by one directly below each seat; for a single seat, the sum of the weight of the passengers on the seat and the amount of water in the
ballast water tank below is equal to a preset value; the device also comprises a
water supply and drainage component for supplying and draining water to each
ballast water tank, and the
water supply and drainage component and each
pressure sensor are electrically connected to a
remote control component; by weighing the passengers on the seats and supplying and draining water to each ballast water tank separately, the sum of the weight of the passengers on the corresponding seats and the weight of the water in the ballast water tank below is equal to and consistent with the preset value, thereby making the manned submersible as a whole balanced and presenting a longitudinal tilt angle of 0, thereby realizing automatic synchronous adjustment, saving time and labor, having good effects, and greatly facilitating
actual use.