The utility model discloses a coded signal conversion circuit which at least comprises a power source circuit, a shaping circuit, a pulse width adjusting circuit and a magnetic encoder analog circuit. The power source circuit, which is connected with the shaping circuit, the pulse width adjusting circuit and the magnetic encoder analog circuit, is used for supplying power for the coded signal conversion circuit; the shaping circuit, which is used for carrying out shaping on input photoelectric encoder signals, outputs the two paths of square wave signals obtained after shaping to the pulse width adjusting circuit; the output end of the pulse width adjusting circuit, which is used for carrying out frequency-halving processing on the signals obtained after shaping, is connected with the magnetic encoder analog circuit; and the magnetic encoder analog circuit, which is used for carrying out coupling and voltage division on the signals obtained after being processed by the pulse width adjusting circuit, outputs magnetic encoder signals after signal coupling and voltage division. The coded signal conversion circuit can collect two paths of photoelectric encoder signals and convert the photoelectric encoder signals into the magnetic encoder signals.