The invention discloses a preparation and crystallization method of phenacetin, and belongs to the field of chemical industry. According to the preparation and crystallization method, p-phenetidine is reacted with an acid in water so as to obtain a p-phenetidine salt; the p-phenetidine salt is reacted with an anhydride in a buffer solution system; after reaction, a mixed solution of water and an organic solvent is added into an obtained reaction solution, and phenacetin crystals are obtained via stirring. Product yield is high; two-step reaction total yield is higher than 92%; the obtained products are crystalline solids; stability is high; purity is high, and is higher than 99%; reaction time is short; reaction conditions are mild; product separation operation is simple; direct filtering separation can be carried out after reaction; and batch production period is shortened greatly.