A vehicle chassis includes: first and second chassis parts; a locking unit including a first engaging part that is pivoted to the first chassis part and that is formed with first and second engaging recesses, a second engaging part mounted on the second chassis part and formed with a tongue such that the tongue pushes the first engaging part to rotate from an unlocking position to a locking position and slides into the first recess during coupling of the first and second chassis parts; and a retaining unit including a retaining part that is pivoted to the first chassis part and that has an engaging end which extends into the second recess when the retaining part is disposed at a retaining position.