The invention relates to a method for preparing n-tetradecane under normal pressure, which comprises the following steps of: (1) mixing glacial acetic acid, zinc powder and alkyl halides of the same grade; (2) dripping hydrochloric acid into the mixture, refluxing, precipitating and separating to obtain a liquid crude product of the n-tetradecane; (3) washing by using acid and alkali to obtain purified liquid of the n-tetradecane; and (4) distilling under reduced pressure to obtain a finished product of the n-tetradecane. The production process is simple, the zinc powder, bromoalkane and the hydrochloric acid are added at the temperature of below 110 DEG C under normal pressure, high-temperature and high-pressure reactions are not performed, and the process has low requirement on production equipment and low danger. In the method, a one-step synthetic mode of reducing the alkyl halides by using hydrogen atoms is adopted, and diethyl ether is replaced by sulfuric acid to remove unsaturated hydrocarbons and alcohols, the safety factor is high, and the condition is easy to control.