The invention discloses an analog signal transmission apparatus based on phase shift PWM modulation. The analog signal transmission apparatus includes an analog signal modulation module, an optical fiber module and a pulse signal demodulation module; the analog signal modulation module is used for sending a to-be-transmitted input signal to the optical fiber module; the optical fiber module is used for transmitting the signal transmitted from the analog signal modulation module to the pulse signal demodulation module; the pulse signal demodulation module is used for receiving the signal transmitted by the optical fiber module; the analog signal modulation module includes an input module, a comparison module and an optical fiber output module that are connected sequentially; and the pulse signal demodulation module includes an optical fiber input module, a subtraction circuit, a filtration circuit and an output module that are connected sequentially. According to the analog signal transmission apparatus, an AD/DA chip may be prevented from being used to transmit an analog signal and the analog signal is transmitted directly by using a basic component such as an amplifier, so the cost of the apparatus is reduced; and as an optical fiber is adopted to transmit the signal, the long-distance high-precision transmission is implemented and the electrical isolation may be implemented.