L4 dimension measuring gauge for petroleum gauge and measuring method thereof

The invention relates to an L4 dimension measuring gauge for a petroleum gauge and a measuring method thereof.The L4 dimension measuring gauge structurally comprises a bottom plate, a panel, a dial indicator, a comparison gauge block and a force applying block, the panel is horizontally arranged above the bottom plate, the dial indicator is arranged on the bottom face of the panel, the comparison gauge block is arranged on the top face of the panel, and the force applying block is arranged on one measuring face of the comparison gauge block; the dial indicator is provided with a measuring needle, the force application block and the gauge to be measured respectively press the measuring needle downwards, and the dial indicator is used for performing zero setting based on the length of the comparison gauge block when the force application block presses the measuring needle downwards and measuring the difference value between the pressing size when the gauge to be measured presses the measuring needle downwards a