Walking tourism is being widely spread in Korea as a new type of tourism. Jeju Olle could be regarded as the first and most popular walking tourism destination in Korea. Using the holt exponential smoothing method, this study forecasted the future demand of Jeju Olle tourism. It also estimated the economic impact of Jeju walking tourism using the I-O analysis. Date were collected from 400 respondents by Internet survey from Dec. 2009 to Jan. 2010. Results showed that demand for walking tourism was predicted to be 12% of total tourists of Jeju by 2015. Results also indicated that demand for Jeju Olle tourism would be 1.7 million by the same year. In addition, the results of I-O analysis indicated that Jeju Olle tourism generated 1.476 billion Won of output impact, 301.8 million Won of value-added, 89.8 million Won of government revenue, and 12,751 jobs. These results imply that a sharp increase in walking tourism and its considerable economic impact will last for a while.