Abstract: According to the principle of electric standing wave,the paper designs a portable lossless anchor length measuring instrument.The control module of gauge uses self-bring AD PIC18LF2520 single chip microcontroller.Scan signal generator module is adopted based on programmable frequency synthesizer CDCE906 from TI company.Besides,diode envelope detector for designing the detector module and LCD for displaying are utilized.The frequency corresponding to the minimum value of the standing wave voltage at the beginning of the anchor is measured through frequency scanning method.In this way,the length of the anchor is measured,which can be displayed on the LCD screen.