Water vapor is a major interesting component in the atmospheric sciences because it affects energy budget of the global climate system and a key element of atmospheric hydrological cycle. There are various instruments measuring the water vapor in the atmosphere. In order to develop a integrated water vapor (IWV) retrieval from 940 nm spectral band measurements by sky radiometer, we first examine water vapor estimated from surface microwave radiometer (MWR) measurements in conjunction with radiosonde observations. Experiments were conducted at Gosan (33.28N, 126.17E), Jeju Island, Korea. Using water vapor profile from radiosonde data as inputs to the MODTRAN radiative transfer model to simulate 940nm channel radiance of the skyradiometer, we developed an retrieval algorithm for the integrated water vapor from sky radiometer measurements. In doing so, we first compared calculated solar radiance with the observed value at 940 nm. Water vapor optical depth is then calculated by subtracting to aerosol optical depth, air molecule optical depth from total optical depth. Retrieved values are then compared with radiosonde-observed IWV as well as MWR-estimated values.