A method for preparing methacrolein from t-butanol, specifically a method for preparing methacrolein by using t-butanol as a starting material, is disclosed, comprising passing the starting material through a fixed bed reactor filled with catalyst, wherein the fixed bed reactor is divided to n reaction zones from the inlet of the starting material to the outlet of the starting material and each zone is filled with catalysts of different catalytic activities; wherein the catalytic activity of the catalyst in the first reaction zone is higher than the catalytic activity of the catalyst in the second reaction zone, and the catalytic activity of the catalyst is gradually increased from the second reaction zone to the last reaction zone; and n is an integer between 3 to 10.