A novel quadrature phase-shift keying (QPSK) demodulator, called the bowknot quadrature phase-shift keying (BQPSK) demodulator, is disclosed. The BQPSK demodulator uses a delay circuit to delay a BQPSK signal and mixes the delayed BQPSK signal with the undelayed BQPSK signal to output an I-channel data signal and a Q-channel data signal. The BQPSK demodulator further uses a phase rotation circuit to demodulate the orthogonal data signals and obtain a recovery clock signal. The BQPSK demodulator neither uses an A/D converter nor uses a quadrature oscillator, featuring high data rate, low power consumption, simple architecture and superior reliability. The BQPSK demodulator can be realized by digital circuits and analog circuits.