Abstract: The problem of the stability of soil slopes has always been a key subject of soil mechanics，and search for the most dangerous sliding surface is the key to make the stability evaluation.The breeding fish algorithm is introduced into the critical slip surface search for the soil slope stability analysis.Based on the standard fish algorithm，the method relies on the law of the natural ecological breeding，which contains the ideas such as eating and mating competition，improving the efficiency of the algorithm，and overcoming its defects of easy to get caught in a local optimum of complex function with the late slow convergence.Combining with two typical examples to search minimum safety factor of slope and the critical sliding surface，the calculation results show that，compared with conventional methods，this method has better convergence effect and precision，and provides a new search method for soil slope stability analysis.

Key words: Slope stability analysis, Sliding surface search, Fish algorithm, Reproduction, Eating competition, Mating competition