Abstract: The paper aims to study the effects of oyster shell soil conditioner on peanut yield and acidified soil amendment in yellow clayey field. The author conducted comparison analysis of the application of oyster shell soil conditioner at the dosage of 2250 kg/hm2 and 1500 kg/hm2 respectively combined with normal fertilizer treatment on peanut grown in yellow clayey field and the application of conventional fertilizer treatment only, to investigate the efficacy of different dosages of oyster shell soil conditioner on peanut yield and acidified soil amendment. The results showed that: the yield of peanut increased by 16.8% and 10.1% respectively after the application of different dosages of oyster shell soil conditioner, and the net income increased by 1750.0 Yuan/hm2 and 900.0 Yuan/hm2, respectively; and the agronomic traits of peanut were also improved; the content of organic matter, alkali- hydrolyzed nitrogen, available phosphorus, available potassium and exchangeable calcium in yellow clayey soil were significantly increased after the application of different dosages of oyster shell soil conditioner, and the soil pH value was also increased by 0.8 and 0.5, respectively. The results provide experimental evidences for increasing peanut yield and improving acidified soil in yellow clayey field.