A study on conservation of outdoor painted sculptures has begun to receive attention as increasing numbers of the sculptures, but it is still in an early stage in South Korea. In the case of a painted outdoor object which has been exhibited in National Museum of Modern and Contemporary Art (MMCA), ‘Black nana’ produced by Niki de Saint Phalle in 1964, deterioration was observed, such as flaking and discolouration of paint layers due to ultraviolet light and a sudden temperature change during an outdoor exhibition. For this reason, prior to treatment of the sculpture, to find out the painting techniques and materials applied, cross section, FT-IR, Raman and Py-GC/Mass were conducted. As a result, the type and colour of the paint agree with results of the other studies as well as deterioration pattern. It is expected that the results of this study will be utilized for treatment proposal and conservation material selection of ‘Black nana’. In addition, to determine the artist's intention of the artist, cooperation with the foundation of Niki de Saint Phalle and artist’s assistants will be carried out.