Oyster mushroom is one of mushrooms that are cultivated and consumed a lot in Korea. P. ostreatus 'Suhan(ASI2504)' is a popluar cultivar because of high quality. But it is difficult for farmers to cultivate, so an alternative cultivar of ‘Suhan’ is demanded continuously. To develop a new variety, parental strains were selected using cultivation characteristics of Pleurotus ostreatus collected home and abroad. P. ostreatus 'Gosol' was developed by the method of Di-Mon crossing between dikaryotic strain P. ostreatus 'Mongdol(ASI0633)' and monokaryotic strain derived from P. ostreatus ‘Yasan(ASI0635)' in 2014. Analysis of the genetic characteristics of the new cultivar 'Gosol' showed a different DNA profile as that of the control strain, 'Suhan’ but a similar DNA profile as those of the parental strains, ‘Yasan’ and 'Mongdol’, when RAPD(Random Amplified Polymorphic DNA) primer URP 3 was used. The optimum temperature for mycelial growth was 25°C for ‘Gosol’ and ‘Suhan’. 'Gosol' was appropriate for middle high temperature to grow, especially 13~18°C. Fruiting body production per bottle was about 124.2g. When compared to the control strain 'Suhan’, the stipe was longer and the individual weight was heavier. But the stipe and the pileus were a little thinner than those of the control strain. ‘Gosol’ was more resistant at high CO2 concentration than the control strain. This new cultivar ‘Gosol’ of Pleurotus ostreatus was characterized dark bluish gray cultivar of oyster mushroom in the color of pileus and higer yield compared to those of other cultivar ‘Suhan’. Therefore, it is suggested that this new cultivar ‘Gosol’ be substitute for ‘Suhan’ in oyster mushroom’s farms.