As a cofferdam structure in the construction of pile foundations in water, the application of steel casing is more and more widespread. Because of the difficulties in construction or demolition, the steel casing is sometimes no longer recycled, thus forming a concrete filled steel tubular composite pile with reinforced concrete materials. In order to find out the influence of pipe bury depth on the vertical bearing characteristics of concrete filled steel tubular composite pile, this paper emphatically studies the influence of pipe bury depth on the side friction resistance and pile end resistance. The results show that the upper steel pipe section (steel casing) is reasonably buried in the 1/3 of the pile length, and when the buried depth of steel pipe section is less than 1/3 pile length, double peak phenomenon will appear in the side friction resistance, when the buried depth of steel pipe section is greater than 1/3 pile length, the double peak phenomenon will gradually disappear. According to the vertical bearing characteristics of concrete filled steel tubular composite pile, the formula for calculating the vertical ultimate bearing capacity of concrete filled steel tubular composite pile is put forward, which will provide theoretical guidance for the design and construction of concrete filled steel tubular composite pile.