Digitization measurement of guide vane angle is an important link when engine digital controller is designed. Working principle of automatic adjust-angle transformer is introduced

and in combination with V / F conversion（ VFC） and equal precision frequency measurement method

hardware and software of the measuring system are designed

using FPGA chip as control core

experimental verification is carried out. Experimental result in lab and airplane show that measuring method is correct and the angle measurement system is reliable and relative error of angle measurement is less than 0. 2 %.