Disclosed are a preparation method for praziquantel and intermediates thereof. The method comprises: a target product praziquantel is obtained by using β-phenethylamine as an initial raw material through the condensation reaction with chloroacetyl chloride, the substitution reaction with ethanolamine, and the acylation reaction with cyclohexanecarbonyl chloride, and then followed by the oxidation reaction and the cyclization reaction. Also disclosed are two key intermediates, namely, a formula IV compound and a formula V compound for preparing the praziquantel. The preparation method is reasonable and simple in technological design, moderate in reaction conditions, economical and environment-friendly raw materials are inexpensive and easy to get, the key intermediates are easy to prepare, the total reaction yield is high (≥ 60%), and the purity of the obtained target product formula I compound praziquantel is high (the HPLC determined purity ≥ 99.8%), so that the industrialized mass production is easy to realize.
