This study examines the restoration project of Sokkuram, and introduces its preliminary plans by the architect Pai Ki Hyung. The restoration project started in 1958 with an inquiry committee of the restoration project, and was completed in 1964. Despite having undergone extensive repair work under Japanese supervision from 1913 and 1923, the repair work caused water leakages inside Sokkuram, and regular cleaning work that began in 1933 caused a lot of damage to the sculpture. In result of the surveys, the top priority of this project was to protect the sculptures inside Sokkuram by improving the environment of the cave. At that time, the architect Mr. Pai participated as a head of the fourth field surveyors to plan the restoration project and to design the preliminary plans. He proposed the installation of a double dome structure to prevent further water leakages on the concrete addition that was built up around the grotto by the Japanese. However, in 1961, the Cultural Heritage Committee of Korea examined the plans of Mr. Pai and immediately rejected them. The factors of the rejection were the omitting of entrance design, system of new double dome structure that presses the existing structure, and these changes that had to be made outside of the drainage plans. The repair work of Sokkuram began in 1961, and the main construction was building double dome structure and entrance installation. In this we realize that Mr. Pai’s double dome structure plans were very important key concept of this project. This study attempts to demonstrate the double dome installations that Mr. Pai initially proposed, which ultimately remains as emblematic factors of Sokkuram’s legacy.