High-precision extraction of fringe frequency is crucial in interferometric particle imaging (IPI) technology. In this paper, a method based on simplified joint interpolation (S-JI) algorithm is proposed to extract the fringe frequency with high speed. The algorithm obtains subpixel-accurate fringe frequency by utilizing both the real and imaginary parts of the Fourier spectrum. Without the need for calculating the frequency offset and performing frequency refinement again (frequency shift), it reduces the algorithm complexity and shortens the computation time. Simulation results show that the processing times of S-JI algorithm saves 2/3, and has the super performance in accuracy and stability of frequency estimation, compared with joint interpolation (JI) algorithm. The relative error of the measured particle diameter is less than 0.3% for standard particles of 25 μm and 70 μm. The results demonstrate that the method presented herein is considerably promising for its application to a high-speed particle field, such as spray, in high accurately measuring particle size.