Abstract: A condensation-recovery device for overpressure gas based on liquefied natural gas (LNG) cold energy, including a tank body and a condensation cavity provided on a bottom thereof. LNG is stored in the condensation cavity to condense boil-off gas (BOG). The condensation cavity includes a vertical hollow tube arranged in the tank body, and an engagement mechanism is provided on a bottom of the vertical hollow tube. The vertical hollow tube is configured such that the gas can experience preliminary contact with the LNG when flowing therein, and the gas will continuously enter the vertical hollow tube under the action of pressure difference. After entering the conical tube, the gas will be distributed along the cavity of the conical tube to spread downward, so as to increase a contact time of the gas and the LNG while avoiding expanding diffusion area of the gas after entering the LNG.