Exhibition vehicle leveling hydraulic system, vehicle and exhibition vehicle leveling method thereof

The invention discloses an unfolding vehicle leveling hydraulic system which comprises an oil tank, an unfolding vehicle leveling oil way, an oil supply way and an unlocking oil way, a first front supporting leg oil cylinder and a second front supporting leg oil cylinder in the unfolding vehicle leveling oil way both adopt double-acting oil cylinders, and a first rear supporting leg oil cylinder and a second rear supporting leg oil cylinder both adopt interference inner locking oil cylinders. The oil supply oil way comprises a variable displacement piston pump, an oil inlet of the variable displacement piston pump is connected with the oil tank, and an oil outlet of the variable displacement piston pump is connected with the first front supporting leg oil cylinder, the second front supporting leg oil cylinder, the first rear supporting leg oil cylinder and the second rear supporting leg oil cylinder and connected with the oil tank through an oil return pipe. An oil inlet of the quantitative gear pump is conne