This research was relative humidity (65, 75, 85 and 95%) growth characteristics of the oak mushroom (Lentinula edodes) 'Nongjingo’. At the relative humidity was 65% in growth chamber. On this condition the moisture content of medium surface was 60.5%. That was lower than other treatments. That condition makes Pileus was 77.1% and stipe was 65%. Among the growth characteristics according to the relative humidity, the pileus diameter at 75% relative humidity were 45.5mm that largest than other treatment and pileus thickness at 75% relative humidity were largest than other treatment. The stipe thickness at 65% relative humidity were 14.8mm that lagest than other treatment. The number of available stipes at 95% relative humidity were 13.3peace/2kg that largest than other treatment. The comparison yield ability of 1 cycle was 104.2g that result in largest than other treatment at 95% relative humidity. This result was associated to the relative humidity of fruiting bodies, the lower relative humidity result in the lower of yield. However, the lower relative humidity result in the higher number of whago, Especially, at the treatment of 65% relative humidity, all the fruit bodies were produced as Whago (dry). Therefore, the higher relative humidity influenced in the higher yield but produced water mushroom. That result was thought that ‘Nongjingo’ would be possible to produce high quality mushroom by adjusting the relative humidity appropriately.