The invention discloses a method for producing adiponitrile with an adipic acid liquid-phase method. A solid phosphoric acid catalyst is adopted, adipic acid and a diluent are added into a reaction still, heating and raw material stirring are conducted during reaction, ammonia gas is supplied after temperature reaches a certain value, and the product is generated after reaction is conducted for a while. A novel environment-friendly adiponitrile synthesis method is adopted. By the adoption of the solid phosphoric acid catalyst, the defects of traditional catalysts are overcome, and catalysis effect is improved.