The invention discloses a construction method for pile foundation drilling of a gravel stratum with a floating pebble layer. Drilling of a pile foundation adopts two pore-forming methods, namely percussion drilling and rotary drilling, at the same time. The problems are solved that as only one pore-forming method is adopted during pile foundation drilling of the gravel stratum with the floating pebble layer under the complex geological condition, the construction period is long, and the pore-forming quality is poor. The incidence of deviated holes and inclined holes is effectively reduced during pore forming of the floating pebble layer as the surface layer, a rotary drilling machine is used for the deep layer, the hole-enlarging rate is effectively reduced, the pore-forming quality of thepile foundation is more excellent, and the work efficiency is higher.