A G-M refrigerator comprises a compressor (1), a gas inlet valve (2), an exhaust valve (3), a regenerator (4), a cylinder (5), a piston (6), a hot cavity (7), a cold cavity (8), a seal ring (9), a driving mechanism (10-12), an annular gap (13), a heat exchanger (14), an orifice valve (18) and a gas reservoir (19). By introducing a phase modulation mechanism, such as the orifice valve (18), the gas reservoir (19) and the like, the working way of gas in the annular gap (13) is changed to be the same with that of a pulse tube refrigerator with the phase modulation mechanism, expansion of the part of the gas is fully utilized for doing work so as to generate the cold effect, loss caused by gas leakage through the seal ring (9) is further eliminated and the performances of the G-M refrigerator are further improved.