The invention discloses a rollover-preventing structure of a tricycle. The structure comprises a frame, and is characterized in that: two rear forks for installing the rear wheels are hinged at the rear part of the frame; a pressure cylinder is arranged on each rear fork to connect with the bearing pole of the frame; the upper cavity of the two pressure cylinder is communicated through pipelines. When the vehicle body turns, the human body and the tricycle all tilt inwards to counteract the centrifugal force; the ground pressure of the outer wheels can be increased through the pressure transmission of the communicated pressure cylinder, the compression of inner pressure cylinder and the equal tensioning of the outer, equalizing the ground pressure of the two rear wheels, thus making the traveling during turning more stable.