Abstract: In order to clarify the effects of the soil conditioner of oyster shell on the paddy soil environment and rice growth, the soil conditioner of oyster shell Tebeigai was selected to carry out the field experiments in the paddy fields with mildly acidified soil and excessive effective content of heavy metals, in order to study the effects of different amounts of conditioner (0, 1500, 3000, and 4500 kg·hm^-2) on the soil pH, heavy metal bioavailability, rice yield and economic benefits. The results showed that, the application of conditioner could obviously relieve the soil acidification, and the pH value was increased by 3.04%-7.02%; reduce the bioavailability of heavy metal, and the contents of available chromium and available lead were decreased by 15.63%-31.25% and 9.05%-14.03%, respectively; increase the supply level of soil calcium, and the content of exchangeable calcium was increased by 7.95%-45.87%. In addition, the conditioner could also improve the yield of rice to a certain extent, but the overall economic benefits decreased with the increase of the amount of conditioner.