The growing demand for new material characterization has become the driving force behind the development of resonant ultrasound spectroscopy (RUS), while a series of personalized requirements, such as small size and irregular shape, make the existing RUS unable to meet the requirements. This paper realizes the sample excitation and the data acquisition of resonance spectrum by using the conventional universal ultrasonic measuring instrument RAM5000/SNAP equipped with the corresponding transducer, and a friendlyinterface instrument based on LabVIEW and MATLAB has been developed, which realizes the automatic control of the instruments. In addition, a high performance optimization algorithm combining particle swarm optimization with simulated annealing algorithm (PSOSA) is proposed to solve the inverse operation of anisotropic material constant. We have accomplished the positive calculation of the sample eigenfrequency and automatic mode analysis with the commercial finite element software COMSOL and Matlab interface program, which can be extended to the measurement of the sample material constants of irregular, arbitrary shape. The sweep range of the instrument is 10 kHz~33 MHz. The sweep resolution is 50 Hz. Since the Ritec measuring instrument has both linear and nonlinear acoustics measurements, it can naturally be expanded into a nonlinear RUS. The elastic constants and piezoelectric constants of anisotropic material of La3Ga5SiO14 (LGS) have been measured. The measurement results are accurate, which verifies the performance of the developed instrument.