The invention discloses a closed-loop identification method for hydropower unit parameter. The method comprises the steps that an actual hydraulic turbine speed-regulation closed-loop system model isestablished, and a corresponding identification system model is determined; an objective function and/or an identification strategy of the hydropower unit parameter identification are determined; excitation signals are inputted in an actual system and an identification system, the output signal of the actual system and the standard signal of the identification signal are acquired; the objective function is used for preprocessing the output signal and the standard signal; an improved antlion algorithm is adopted to conduct a parameter identification to the hydraulic turbine speed-regulation closed-loop system according to a preprocess result; the optimal identification parameter of the a hydropower unit is acquired according to the identification strategy. Based on a standard improved antlion algorithm, a particle swarm optimization algorithm is integrated, a chaotic logistic mutation operator is introduced, a new particle is acquired by adopting the method of combining parallel and serial ways in the process of chaotic variation, so that the standard antlion algorithm is improved. The closed-loop identification method for hydropower unit parameter has the advantages of being high in convergence rate, easy in realization, strong in universality, and the identification accuracy is improved effectively.