The invention relates to a method for preparing pyrrolidone by using levulinic acid, belonging to the technical field of chemical intermediate production methods. According to the method, the levulinic acid is converted into N-substituted-5-methyl pyrrolidone in presence of a semi-sandwich iridium catalyst by taking amines as raw materials in a formic acid buffer solution system at the temperature of 50-220 DEG C. According to the technical scheme, the levulinic acid is converted into the N-substituted-5-methyl pyrrolidone by taking the semi-sandwich iridium catalyst as a catalyst at lower temperature in the formic acid buffer solution system; a product is convenient to separate and high in yield, and has a higher application value; the method is simple in technology and wide in market prospect.