Aiming at the problem of improper ash blowing operation on the heating surface of coal-fired boilers, this paper proposes a soot blowing optimization method based on Gamma acceleration soot deposition model with the aim of minimizing soot blowing cost. In this paper, firstly, in the case that the ash accumulation state on the heating surface of the boiler is continuously monotonically increasing, a continuous non-negative random variable obeying the exponential distribution is used to express the ash velocity of the boiler heating area, and an accelerated ash accumulation model is established; Secondly, under the circumstance the ash process is regarded as a similar process to the Gamma model. An optimized model for ash blowing on the heating surface of the boiler is established to minimize the average cost. Taking the ash state of the heating area of a 300 MW coal-fired economizer as an example, the PSO algorithm is used to optimize the average cost of ash blowing, obtaining the best soot blowing times and soot blowing thresholds on the heating surface of the boiler, so that making the average cost of the soot blowing on the heating surface of the boiler smallest. It also illustrates the feasibility of the minimum cost rate optimization model proposed in this paper.