The reproductive characteristics of Steneotarsonmus spinki were studied in this paper. It was discovered for the first time that S. spinki is parthenogenetic. All of the descendants of virgin females were males. But the mother female could mate with its male offspring, and then produced both female and male mites. The span of a generation was short, which was 13.6–8.5 days at 25–30°C. Female adults had relatively long longevity and oviposition period, which were 31.6–23.6 days and 25.6–17.6 days respectively. A mated female mite could produce 55.5 eggs on average in the laboratory at 24.5–35.4°C (June 18 July 11). A virgin female adult in a mite-free rice seedling could develop to an average of 79.4 mites at 24.1–35.3°C (June 22 to July 9) in 17 days. This study showed that this mite had a high potential for population growth.