A weighted Bayesian inversion method is proposed for estimation of unimodal particle size distribution in multi-angle dynamic light scattering measurements. Particle size informiation distribution in autocorrelation function is used as base and adjustment parameters as exponent in the weight coefficient. Traditional Bayesian inversion method is recovered. Simulation and experimental data at different noise levels show that weighted Bayesian inversion method obtains inversion results with smaller distribution error. It weakens effectively influence of data noise and improves accuracy of particle size distribution.