The invention discloses a construction improvement method of a surface runoff collection small area, and belongs to the technical field of water and soil conservation. According to the method, on a mountain slope where surface runoff hydrology is required to be studied, asbestos tiles are used as a fence material, a waste iron oil barrel is taken as a runoff collection barrel, and a shunt barrel is arranged at the same time, so that the runoff volume collected under a rainstorm condition is still accurate. The runoff collection barrel is covered with the asbestos tiles, and the computation process of the runoff volume is simplified. Red bricks and cement mortar are replaced with the low-cost asbestos tiles and the waste iron oil barrel, so that the construction is simple and convenient, the cost is low, an original soil structure is not damaged, dismantling is facilitated, the expensive dismantling cost for post maintenance is not caused, and the collected runoff volume data can accurately reflect the actual water and soil loss volume.