High-cycle fatigue tests were carried out to investigate the effects of stress ratio on the fatigue ultimate strength and S-N fatigue life for 0Cr18Ni9 stainless steel welded joints. The results show that the fatigue life increases with stress ratio under the given maximum stress. Based on the tests results， the Goodman and Walker high-cycle fatigue life prediction models are obtained to reflect the effects of stress ratio. And the comparison also reveals that the Walker model predicted life coincides with the tests data better than Goodman model with the fact that the former models'' data distributes on the more narrow band.