Disclosed are a method of preparing allyl alcohol and allyl alcohol prepared thereby. The method of preparing allyl alcohol includes adding glycerol with formic acid in an amount of 0.8˜2 equivalents relative to 1 equivalent of glycerol, and increasing a reaction temperature to 220˜260° C. from room temperature at a heating rate of 2.0˜7.0° C./min so that glycerol and formic acid are reacted.