A construction process for the composite pile foundation which consists of the expanded belled base and the pile shaft, the construction process comprising the steps of: a) Aligning the pile tip at the pile location and place the casing at the top of the pile tip; b) Lifting the heavy hammer to enter the casing, repeatedly lift the heavy hammer to reach the given height and back press the casing, let it fall freely to ram the pile tip and the soil until a hole forms at the pile location; c) Lifting the heavy hammer higher than the feed inlet of the casing and fill solid material from the inlet into the casing; d) Ramming the above-mentioned solid material and repeat the filling and ramming operations; e) Controlling the penetration of the last three blows; f) Filling graded aggregate or stiff consistency concrete and repeatedly ram it to form the expanded belled base; g) pull out the casing; h) Aligning the pile shaft at the pile hole and repeatedly back press and blow slightly with the heavy hammer to drive the pile shaft into the pile bole and fix and connect it with the expanded belled base; i) Controlling the penetration of the last three bouts and form the pile. The invention offers the advantages of high bearing capacity, small settlement, short pile shaft, low engineering cost, simple construction, short construction period, easy quality control etc.