Abstract: In order to solve the mixed nonlinear multi-objective optimization problem of discrete/continuous variables under the multi-constraint conditions of spherical transducer, the electrical-mechanical-acoustic model of spherical transducer is established based on the equivalent circuit theory. The multi-objective optimization mathematical model of spherical transducer is constructed. The source level, input electric power and mass are taken as the optimization objective functions, and the material property parameters, structural size parameters, frequency range and input voltage are taken as the design variables. Besides, the physical properties such as piezoelectric ceramic depolarization, structural strength limit, power capacity and the value of design variables are taken as constraints. The multi-objective optimization design of spherical transducer is carried out by using the Non-dominated Sorting Genetic Algorithm-II (NSGA-II), and the Pareto front solution set are obtained. The effectiveness of the optimization results are verified by experiments. The results show that the transducer prototype designed and manufactured by the multi-objective optimization method reduces the input power by 32.8% and the mass by 27.4% under the premise of meeting the requirements of the radiation sound source level. The research results can provide a reference for the optimization design of transmitting transducer under severe conditions.