This study was carried out to investigate the characteristics and seasonal fluctuation of commLinity structure of Coleoptera and Araneina, inhabited on the crown of Korean pine (Piveus kordzensis). To do this four artificial stands of Korean pine, A(11-years old), B(21-years old), C(31-years old), and D (46-years old) were selected in Sudong-myen, Namyangju-gun, Kyeonggi-do, After spraying the insecticide (DDVP), the Arthropodas fallen to the vinyl cloth wrapper (6m × 6m) were collected and identified. The field collection was carried out for two years, 1986-1987 at interval of one month. 1. The total number of Coleoptera observed in investigated stands is 107 species of 85 genera under 35 families ; 82 species of 66 genera under 27 families in 1986 and 72 species of 52 genera under 30 families in 1987. The total number of Araneina is 77 species of 48 genera under 14 families : 53 species of 34 genera under 13 families in 1986 and 50 species of 34 genera under 12 families in 1987. 2. The dominant and subdominant species of Coleoptera are Podabrus sp. (Cantharidae) and Cotops sp. (Coapidae). In Araneina, dominant species is Leucauge subblanda (Tetragnathidae) and subdominant species Clubiona jucunda (Clubionidae). 3. The species number of Coleoptera attained the maximum value in May and then decreased gradually, while that of Araneina displayed relatively narrow monthly fluctuation with two peaks in May and August. Monthly changes of individual numbers are similar to those of species number in Coleoptera and Araneina, 4. Species number of Coleoptera was the highest in stand B and D, and that of Araneina was in stand A. But stand C thinned in the previous year cvas poor in the number of species of Coleoptera and Araneina. The monthly changes of species and individual number in each stand showed a similar tendency. 5. Comparison of the community coefficient between stands didn`t show any special tendency in Coleoptera and Araneina. But in Araneina, relatively high values of community coefficient were observed between stand B and C, and also between C and D. 6. Dominance index of Coleoptera obtained the minimum value in June and increased after that, It showed inverse relation to the monthly changes of species and individual number. In Araneina, it was the highest in May, and the lowest in September. It showed similar pattern to the monthly changes of species and individual numbers until May, and showed inverse relation after that. 7. Monthly changes of diversity indices were similar to those of species and individual number, but showed inverse relation to those of dominance index in Coleoptera and Araneina.