The impact of scattering angle on nano-particles measurement is studied by using the method of correlation spectroscopy. The system of nano-particles experiment using the method of correlation spectroscopy is reformed to carry out the measurement of nano-particles at different scattering angles. Particles of 30-nanometer and 200-nanometer were mixed in different proportions, which were measured at scattering angles of 90 degrees and 165 degrees. It shows that accurate measurements can be realized at the two angles for the single particle group. While for the mixed particle group, the experiment results are affected by the mixing ratio of two kinds of particles. Better measurement results were got at the scattering angle of 165 degrees. Therefore the usage of large scattering angle contributes to the inversion of particle size for the hybrid nano-particles size measurement.