The invention discloses an external ripple enhanced steel-plastic composite winding pipe and a machining method thereof. The main structure of the pipe is that a steel strip is sealed between a plastic covering layer and an outer wall of a pipe body to form external ripples; the steel strip is of a hollow pipe structure with a closed cross section and tightly winds the outer wall of the pipe body in a winding and bending manner, so that an equal-distance spiral shape is formed; the bottom end, which is tightly close to the outer wall of the pipe body, of the steel strip is wider than the top end, far away from the outer wall, of the steel strip; and the cross section of the top end of the steel strip is in an arc shape. According to the pipe disclosed by the invention, the steel strip is self-stressed when the pipe is stressed in the radial direction so that force is not axially applied to the pipe body, axial tearing of the pipe body or the plastic covering layer is effectively prevented, and the stressing capability and the practicability of the pipe are greatly improved; the steel strip also can be made of a steel plate with a relatively thin wall for achieving a relatively great pressure bearing effect, materials are saved and the cost of the materials is further reduced; the combination of steel and plastic is greatly improved by strengthened occlusion holes, and thus steel and plastic separation caused by the fact that the stress on the pipe is too great is effectively avoided; and the pipe is scientific and reasonable in structure, high in durability, high in practicability and wide in market prospect, and the technical difficulties of partial cracks and the like in the prior art are solved.