Abstract: Through testing the type inspection of theФ75 round steel mechanical joints, as for China has not yet established type inspection technical regulations of large-diameter round steel mechanical joints, Referring to General Technical Specification for Mechanical Splicing of Bars JGJ107-2003. we have had meaningful exploration for the process and methods, successfully accomplished the items of the type inspection. Due to the particularly large diameter round bar, in a sense, the test fills the domestic blanks of this kind of tests.