The purpose of this study is to find out the appearing era of Kyungju city forests, study the backgrounds about origination and disappearance, and to analyze location, function, and plant composition in order to interpret the transition of them. In this study, we divide four eras ; ancient Silla era, Silla era, Korea era, Chosun era. Kyungju city forests in each era are as follows ; Ancient Silla era : Najung(蘿井), Oreunglim(五陵林), Ajinpo(阿珍浦), Kyelim(鷄林), Chunkyunglim(天鏡林), Sineulim(神遊林)Silla era : Oangkasu(王家藪), Bonghoangdae(鳳凰臺), Koyangsu(高陽藪), Limjungsu(林井藪), Jibuklim(枝北林), Youlim(柳林), Seobulyublim(西部獵林), Youlim(栗林) Korea era : Olisu(五里藪), Hanjisu(閑地藪), Dongjungsu(東亭藪), Bibosu(裨補藪) Chonsun era : Namjungsu(南亭藪), Oeodaesu(魚岱藪), Koolitaegmog(校里宅木), Koseongsu(古城藪) The results of this study can be summarized as follows ; 1. The origination of Kyungju city forests in ancient Silla era was affected by the in fluence of native belief(for example, Najung(蘿井)ㆍOreunglim(五陵林)ㆍAjinpo(阿珍浦)ㆍKyelim(鷄林) as a birth place and tomb of three founders in Silla ; 'Heolim(墟林)' as a common title) and then by the influence of Buddhism(for example, Chunkyunglirn(天鏡林) as a site of Heungroun temple, Sineulim(新遊林) as a site of Sachunoang temple). And Kyungju city forests in Silla and Korea era usually appeared by the influence of Fengshui(Bonghoangdae(鳳凰臺)ㆍHanjisu(閑地藪), Bibosu(裨補藪)) and by the practical function(Koyangsu(高陽藪)ㆍLimjungsu(林井藪), Jibuklim(枝北林)ㆍYoulim(柳林)ㆍSeobulyublim(西部獵林) as a hunting ground. Oangkasu(王家藪)ㆍOlisu(五里藪) for prevention of floods, Youlim(栗林)ㆍDongjungsu(東亭藪) as a recreation place). At last, Kyungju city forests in Chosun era mostly have various practical functions (Namjungsu(南亭藪) as a recreation place, Oeodaesu(魚岱藪) for prevention of floods, Koolitaegmog(校里宅木) for protection against wind, Koseongsu(古城藪) for fruit production). 2. The cause of disappearance of Kyungju city forests are the construction of temple (Chunkyunglim(天鏡林)ㆍSineulim(新遊林)), land and house development(Oangkasu(王家藪)ㆍLimjungsut(林井藪)ㆍJibuklim(枝北林)ㆍSeobulyublim(西部獵林)ㆍHanjisu(閑地藪)), and river improvement and road development(Olisu(五里藪)ㆍDongjungsu(東亭藪)ㆍNamjungsu(南井藪)ㆍOeodaesu(魚岱藪)ㆍKoseo ngsu(高城藪)). 3. Kyungju city forests in ancient Silla era have the function of protection against wind(when we considered the center of Kyungju at that time, the directions of wind are south-south west and south east) and prevention of floods at Namchun in the south of Kyung city. Kyungju city forests in Silla and Korea era have the function of protection against wind from north wind and prevention of floods at Bugchun in the north of Kyungju city. And Kyungju city forests in Chosun era have various functions the same as above-mentioned. 4. The plant of ancient Silla era's forests usually are coniferous trees something like a pine tree except Kyelim(鷄林), but since Silla era, various broadleaved trees have appeared inside of Kyungju city forests. We must reflect profoundly that since the era of Japanese imperialism, these kinds of Kyungju city forests have not been planted.