Variable-cross section tubular pile connector

The utility model provides a variable-cross section tubular pile connector. Two sides of a metal ring are respectively and fixedly connected with two metal circular pipes with different diameters, the outer diameter of the metal ring is as same as that of a port of a cooperatively-used large concrete tubular pile, and the outer diameters of the metal circular pipes are respectively fit with the inner diameter of the port of each cooperatively-used concrete tubular pile. The large metal circular pipe of the variable-cross section tubular pile connector is inserted into the port of the large concrete tubular pile when the variable-cross section tubular pile connector is used, so that the small metal circular pipe is inserted into a port of a small concrete tubular pile, and the variable-cross section tubular pile connector is respectively welded with metal aglet heads at two ends of each concrete tubular pile, so that the two concrete tubular piles with different cross sections can be connected with each other.