The present invention relates to a single-chain circular RNA having a sustained or slow-releasing RNA interference effect, characterized in that the single-chain circular RNA comprises a sense strand sequence, an antisense strand sequence complementary to the sense strand sequence, identical or different two loop sequences between the sense strand and the antisense strand, connecting both strands, wherein the sense strand and the antisense strand are paired to form a stem.本發明係關於一種具有持續性或緩釋性RNA干擾作用之單股環狀RNA，其特徵在於：含有有義股序列、與該有義股序列互補之反義股序列、於該有義股與該反義股之間結合二者之相同或不同的2個環序列，且該有義股與該反義股配對而形成莖。
