A foldable child's tricycle and a folding method thereof are provided, wherein the foldable child's tricycle comprises a body frame and a handlebar (2) arranged in the front of the body frame; wherein the body frame includes a head tube (6), an upper connecting rod assembly (7), a lower connecting rod assembly (8), a push rod assembly (9), and a supporting rod (10); the upper connecting rod assembly (7), the head tube (6), the lower connecting rod assembly (8), and the supporting rod (10) form a four-bar linkage; the push rod assembly (9) is rotatably connected to the upper connecting rod assembly (7), and is fixed to or separated from the lower connecting rod assembly (8) via a locking device; when folding, firstly unlocking the locking device; then pulling the push rod assembly (9) upwardly such that the push rod assembly (9) is separated from the lower connecting rod assembly (8); finally turning over the push rod assembly (9) forwardly, and the folding volume thereof is small.