Canal system buildings in small irrigation areas include water drop design drawings and steep slope design drawings. The water drop is 80cm wide, the drop is about 3m, the steep slope is 1m wide, and the drop is nearly 30m. The bottom of the canal is curved, so the construction is not very good. It is easier to make a rectangle or trapezoid, and it is appropriate to set a joint at 10m, with a slope of 6%. The drawings meet the requirements of the preliminary design and are consistent with the atlas of small and medium-sized canal system buildings,