A special gauge for calibration of a length measuring machine is applied to calibration of a model N3M-11 length measuring machine. The special gauge for calibration of a length measuring machine is characterized by comprising a sleeve and a threaded connecting part, wherein threads are arranged in the middle of the threaded part, and the sleeve is transversely installed at one end of the threaded connecting part. The special gauge for calibration of a length measuring machine has the advantages of replacing the 1m gage blocks, saving purchase cost and gage block verification cost for measuring value transfer in subsequent verification, and improving the efficiency of calibration work.