The invention discloses a digital demodulation system for three-floated gyroscopes, which comprises an angle sensor, a signal generator, a preamplifier, an A/D conversion circuit, a constant-temperature crystal oscillator, an FPGA field programmable logic device, an RS/485 interface circuit, and a principal computer. The angle sensor is used for loading a collected signal to be measured on a standard sine excitation signal generated by the signal generator to form a sine wave modulation waveform signal. The preamplifier is used for amplifying the signal. The A/D conversion circuit is used for performing analog-to-digital conversion on the signal to get a digital signal to be measured and a standard digital signal. The FPGA field programmable logic device is used for calculating the digital signal to be measured according to the standard digital signal and outputting the calculation result to the principal computer through the RS/485 interface circuit. Through the system of the invention, fast and high-precision digital demodulation of a to-be-measured signal collected by the angle sensor is realized.