The boring machine of construction machinery has the advantages of quick correction, accuracy, advanced structure and quick installation, which is convenient for installation and use in narrow space; it has strong power; the boring bar is made of bearing steel by special process, with high strength, high hardness, high precision, good toughness, hard chrome plating, rust free and good wear resistance. The spindle box (power head) can be installed at any position of the boring bar, which is simple and convenient to fix; the bearing support is equipped with imported two rows of self-aligning cylindrical roller bearings, with high precision and high rigidity; the end tool holder can automatically move the tool forward and backward, with adjustable feed rate, and the machine can be disassembled for easy installation and disassembly.