It took almost 50 years for Korean detainee in Sakhalin to start to visit and return to Korea since 1990’s after the end of World War Ⅱ. There was much meandering and steps before the temporary visit and permanent return to Korea is possible. But little is known of Park Rho-Hak, what and how he has done for the repatriation movement of Korean detainee in Sakhalin. This essay addresses Park’s life before being mobilized to Sakhakin, his life and re-marriage to Kazuko, the Japanese woman in Sakhalin after war, his activities since the return to Japan, the league of Korean in Japan who was detained in Sakhalin, so-called ‘Park’s letters from Korean in Sakhalin’ and ‘Park’s list of Korean in Sakhalin’, the realization of ‘temporary visit to Japan and family reunion’ and ‘temporary visit to Korea via Japan’, and so on. In summary, my discussion of Park Rho-Hak, his relationship and activities has developed four main points: First, I found out and reconstructed his background before being mobilized to Sakhalin, the forced labor at Sakhalin, detainment at Sakhalin, re-marriage to a Japanese woman, return to Japan, organizing the league of Korean in Japan who was detained in Sakhalin, and activities for repatriations of Korean from Sakhalin. Second, I found out and reconstructed that how the so-called ‘Park’s letters from Korean in Sakhalin’ was transmitted to the family in Korea and vice versa, and how the ‘Park’s list of Korean in Sakhalin’ was listed up and submitted to the governments of Korean, Japan, and Russian Soviet, even to the International Organization such as Red Cross. Third, this article reviewed the key personnel such as ministers, bureaucrats, politicians, lawyers, civic activists, and their role, who Park Rho-Hak has contacted and enter into a relationship for the purpose of repatriation of Korean in Sakhalin. Fourth, I found out and reassessed that Park Rho-Hak devised the ideas of ‘temporary visit to Japan and family reunion’ and ‘temporary visit to Korea via Japan’ and realized those ideas, considering all conditions of that times. Park’s life and efforts for the repatriation of Korean detainee in Sakhalin is the foundation stone and history of the repatriation of Korean detainee in Sakhalin, also, it means the path he has followed.