The invention relates to a self-adaptive anti-sloshing-impact device of a dangerous goods storage vehicle. The self-adaptive anti-sloshing-impact device comprises a storage main tank, a discharging push plate, a multi-stage hydraulic cylinder, a hydraulic buffer, a selection switch, an operating handle, a proportional valve and an inclination sensor. Liquid dangerous goods leaking to the ground are sucked into the storage main tank through vacuum negative pressure, the multi-stage hydraulic cylinder is controlled to move the discharging push plate to the middle of the storage main tank duringtransportation of the dangerous goods, and the discharging push plate acts as an anti-sloshing plate at the time. According to the pitching posture of the storage main tank detected by the inclinationsensor, the longitudinal position of the discharging push plate is automatically changed, the sloshing impact of liquid applied to the discharging push plate is transmitted to the hydraulic buffer through the multi-stage hydraulic cylinder, hydraulic oil in the hydraulic buffer is urged to pass through a throttling hole at a high speed, the kinetic energy of the liquid is converted into heat energy, and the impact of the liquid in the storage main tank is attenuated, so that the driving safety is improved.