The invention discloses a load lock chamber including a cavity provided with a first vacuum valve and a second vacuum valve; a chuck plate provided with a clamping seat accommodated in the cavity, wherein the clamping seat is used for placing the substrates and the outer edge of the clamping seat is provided with at least two grooves; a support frame which is accommodated in the cavity, arranged on the clamping seat and provided with at least two connection parts; and at least one lifting mechanism used for ascending or descending the connection parts of the support frame. A plurality of support platforms extend horizontally in a protruding manner from each connection part of the support frame towards the axis direction of the support frame. Each support platform is provided with a bearing part. The bearing parts are arranged in corresponding grooves of the clamping seat. Bearing parts of the same layer on the connection parts are parallel to the clamping seat and capable of supporting one substrate. The load lock chamber is simple in structure and capable of processing a plurality of substrates so that process efficiency is improved. The invention also discloses a method of using the load lock chamber to process the substrates.