In order to investigate circulating fatigue life performance of the composite overwrapped pressure vessel(COPV), the 30 MPa,50 L vessel on satellite was regarded as an object, whose liner material is titanium and whose complex layer material is carbon fiber T1000/epoxy resin BA202. A fatigue life prediction technique and factors affecting the fatigue life were introduced to supply the reference for design of the COPV. To utilize low-level cyclic fatigue theory, and to combine ANSYS simulation model of multi-layer winding, the total strain variation of the liner was obtained and the fatigue life of COPV was forecasted after increase and decompression again and again. According to the measured value of vessel fatigue limit, the measured value of vessel with wall thickness of 0.8 mm was 378 times, and the calculated value was consistent with the measured. Research results show that: the fatigue life prediction technique is correct,self-tension treatment can expand the elastic working range of the vessel and improve the fatigue life, and the internal pressure load corresponding to the material yield limit is often the best self-tension pressure in the fatigue design.