A method for demodulating a signal implemented by a mobile terminal, the method comprising steps of: acquiring a reference clock signal provided by a power management unit 'PMU' in the mobile terminal; determining a velocity of the mobile terminal, and determining, according to the velocity, a Doppler frequency shift value generated when the mobile terminal receives a RF signal transmitted by a base station; and demodulating, according to the reference clock signal and the Doppler frequency shift value, the received RF signal transmitted by the base station; characterized in that, the step of determining a velocity of the mobile terminal, and determining, according to the velocity, a Doppler frequency shift value generated when the mobile terminal receives a RF signal transmitted by a base station, comprises steps of: determining (S301, S602) velocity vectors of the mobile terminal at two set time points through a global positioning system, GPS; determining (S302, S603) a modulus value |ΔV| of a difference between the velocity vectors at the two set time points; determining (S303, S604) an angle α between directions of the velocity vectors at the two set time points; and determining (S304, S605) the Doppler frequency shift value Fd generated when the mobile terminal receives the RF signal transmitted by the base station according to a formula Fd=|ΔV|*cosα/λ for calculating a Doppler frequency shift value, where λ is a radio wavelength; or searching for the Doppler frequency shift value corresponding to the determined |ΔV| and α in a preset relationship mapping between |ΔV| and α value ranges and Doppler frequency shift values. acquiring a reference clock signal provided by a power management unit 'PMU' in the mobile terminal; determining a velocity of the mobile terminal, and determining, according to the velocity, a Doppler frequency shift value generated when the mobile terminal receives a RF signal transmitted by a base station; and demodulating, according to the reference clock signal and the Doppler frequency shift value, the received RF signal transmitted by the base station; characterized in that, the step of determining a velocity of the mobile terminal, and determining, according to the velocity, a Doppler frequency shift value generated when the mobile terminal receives a RF signal transmitted by a base station, comprises steps of: determining (S301, S602) velocity vectors of the mobile terminal at two set time points through a global positioning system, GPS; determining (S302, S603) a modulus value |ΔV| of a difference between the velocity vectors at the two set time points; determining (S303, S604) an angle α between directions of the velocity vectors at the two set time points; and determining (S304, S605) the Doppler frequency shift value Fd generated when the mobile terminal receives the RF signal transmitted by the base station according to a formula Fd=|ΔV|*cosα/λ for calculating a Doppler frequency shift value, where λ is a radio wavelength; or searching for the Doppler frequency shift value corresponding to the determined |ΔV| and α in a preset relationship mapping between |ΔV| and α value ranges and Doppler frequency shift values. determining (S301, S602) velocity vectors of the mobile terminal at two set time points through a global positioning system, GPS; determining (S302, S603) a modulus value |ΔV| of a difference between the velocity vectors at the two set time points; determining (S303, S604) an angle α between directions of the velocity vectors at the two set time points; and determining (S304, S605) the Doppler frequency shift value Fd generated when the mobile terminal receives the RF signal transmitted by the base station according to a formula Fd=|ΔV|*cosα/λ for calculating a Doppler frequency shift value, where λ is a radio wavelength; or searching for the Doppler frequency shift value corresponding to the determined |ΔV| and α in a preset relationship mapping between |ΔV| and α value ranges and Doppler frequency shift values.