Production of reanalysis data is important since it contributes to develop all fields of atmospheric sciences and to profit national economy. The developed countries such as USA, EU, and Japan have manufactured the global reanalysis data since the 1990s, but their data present a lack of detailed regional climates. For those who need to analyze the regional climate in/around Korea, a high-resolution reanalysis data should essentially be made. This study reviewed the existing reanalysis data and the applications, and the available observations for the data production. We also investigated the opinions and needs of the potential data users in Korea. We suggest the specifications of the data to have the domain of 55-5N, 80-150E (which includes Mongolia and most Southeast Asian countries), the spatial resolution of 10-20 km, and the period of most recent 30 years. With the specifications and climate models operated in KMA, this study argues that production of the reanalysis data with functional climate information is feasible in both technical and economic aspects. Finally, for successful data production, the framework of the future reanalysis data project was suggested.