According to the report of the United Nations (1998), one child has died at a time at 8 seconds owing to water-related illness, 80% of sick cause in a developing country is sewage, and there is no sewer institution in 50% of world population. 2, 500 million people who cannot drink safe sterilized water exist in the world. The way things stand, a situation is getting worse steadily. In this research, experimental examination was performed about the method for manufacturing water simple and cheap, and safe in view of a water shortage in a developmental-stage area, and the point that safe water is not supplied especially. Consequently, the thin laminar flow multi-stage processing process of having used the photocatalyst was developed as the suitable water purification method for a developing country. According to this method, the coliform bacteria count was removed by the conditions of 1cm in thickness of thin laminar flow, and 7cm of distance with a light source 100% in 5 hours after a processing start for holding time 3 hours. In order to evaluate water quality purification performance, the COD reduction which is a water pollution index, and the coliform bacteria count which are the health of water and the index of safety were examined.