Abstract: Based on weekly price data from January 2009 to September 2016 of crude oil, soybean, corn, rice and wheat, this paper empirically explored the transmission effect of oil price on grain price and its time-varying characteristics by the rolling cointegration model. Results show that: 1) the transmission effect of oil price on soybean price is the strongest, and soybean price can adjust to long-term equilibrium with the highest speed; 2) the transmission effect of rising oil price on corn price is much stronger than others, but the effect is not significant when oil price is dropping; and 3) the transmission effect of oil price on rice price has been increasing significantly for years; but there is less sensitive reaction from wheat price to the oil price. In summary, upward trending crude oil price has stronger influence on grain price, and the transmission effect is imposed on those grain products with higher degree of marketization and are directly related bioenergy, such as soybean and corn, first, and then on the entire grain market.