The invention discloses a method for improving the non-displacement pile composite foundation bearing capacity. As for a limestone area, a dip angle of a bed rock face is larger than or equal to 60 degrees, a soft rock strata is arranged on the upper surface of the bed rock, a composite foundation is constructed on a non-displacement pile in the area, as for a pile body with the non-displacement pile which is tested to be unqualified in bearing capacity, a static pile press machine and a pile feeding device are installed on the non-displacement pile, re-pressing is carried out by the static pile press machine on the non-displacement pile at two to four times, in each re-pressing process, the pile pressing force is gradually increased from zero through a hydraulic device of the static pile press machine, until the maximum pressing force is achieved, at the maximum pile pressing force stable pressure stabilization time, unloading is carried out until the value is zero, and then the next re-pressing is carried out. According to the method, pile end supporting conditions of the non-displacement pile are changed in a re-pressing mode, therefore, the pile end of the non-displacement pile is in sufficient contact with the bed rock, surrounding soft soil is pressed to a certain degree, and accordingly the foundation pile bearing capacity is greatly improved. The bearing capacity of a single pile can be improved by 1 to 3 times, and the composite foundation bearing capacity is correspondingly increased by 1 to 3 times.