The invention discloses a method of using a 3D single-arm measurement marking machine, which comprises the following steps: first, installing a fixed block on a Y-axis marking arm of a 3D single-arm measurement marking machine, adjusting one first driving mechanism to enable an output shaft to drive a marking head to stretch out, loosening a connecting part, adjusting the angle of a mounting head to make the outstretched marking head aligned with a work piece, and marking the work piece through motion of the 3D single-arm measurement marking machine; when the marking head wears out, using the first driving mechanism to take the worn marking head back, and making another first driving mechanism drive another marking head to stretch out; and finally, moving the mounting head through a second driving mechanism to make the outstretched marking head move to the position of the replaced marking head, and continuing to mark the work piece. Multiple marking heads can be installed simultaneously, and the work efficiency is improved. After a marking head is replaced, the work piece can be located quickly. The accuracy of marking is improved.