From the soils collected seasonally at the 0.5~2cm and 50$pm$1cm depths of riverside, different strains of actinomycetes were isolated and identified to the genus. At the 0.5~2cm depth, Streptomyces and rare actinomycetes were in total 73 and 62 strains, respectively. Streptomyces was approximately 2-fold more in spring and autumn than summer, and rare actinomycetes was at least 4-fold more in autumn and winter than spring. At the 50$pm$1cm depth, Streptomyces and rare actinomycetes were in total isolated 53 and 41 strains, and these were at least 2-fold more diverse in autumn than spring, summer, and winter.