The invention discloses a peanut peptide preparation method for enzymatically decomposing thermal-crushed peanut meal step by step with double neutral protease. The method is characterized in that the thermal-crushed peanut meal is enzymatically decomposed through neutral protease and compound protease step by step, and experiments are carried out to determine the optimal enzymatic decomposing condition and the addition of the neutral protease and compound protease. The peanut peptide preparation method is simple in process, mild in condition, short in preparation time, low in preparation cost, low in yield of oligopeptide, and high in degree of hydrolysis, and the utilization rate of the thermal-crushed peanut meal is effectively raised. According to the method, the yield of oligopeptide and the degree of hydrolysis are greatly improved, the yield of oligopeptide reaches 85.20%, and the degree of hydrolysis reaches 40.55%; in addition, the molecular weight of the obtained peanut peptide is concentrated to be below 1000Da, and the peanut peptide with the molecular weight being less than 1000Da accounts for 95.57%, so that the prepared peanut peptide is easily absorbed and utilized by a human body; and the peanut peptide is high in functional activity and high in nutritional value. The method has the advantages of being simple in process, mild in condition, high in yield of oligopeptide, capable of producing peanut peptide with small molecular weight, and suitable for massive industrial production.