Abstract: The toxicities of carbonyl sulfide (COS) for some pests of vegetables and horticulture at different dosage and exposure time were investigated. The results showed that COS had effect on killing 13 tested species of vegetable and horticultural pests, and but no effect on two species of nematodes. The mortality of insects increased with the increase of the dosage and exposure time of COS. At the condition of (20±1)°C or 25°C, COS with the dosage of 40g/m3 for an exposure time of 2h can completely kill these pests, but there were no effect on the nematodes in soil. The results of COS effects on fruits, vegetables, cut flowers, lily bulbs and potted ornamental plants showed that there were no phytotoxic effects of COS on fruits and vegetables under the condition of COS with the dosage of 40g/m3 and for an exposure time of 2h. The COS fumigation has no damage to flowers, but there were serious damages to leaves, especially to plant of Orchidaceae and Bromeliaceae. The fumigation causes symptoms of dried-up, necrosis on the leaves or loss the value of ornamental.