Based on Swedish slices limited equilibrium method, a new computation formula of stability safety factor is presented for interior stability analysis of soil nailing wall in non-homogeneous soil. A new genetic algorithm is put forward by adopting dynamic self-adaptive technology and nonstandard genetic operators. Applying the dynamic self-adaptive technology and nonstandard genetic operators into the field of soil-nailing wall interior stability analysis, the dynamic adaptive genetic algorithm for searching the arbitrary critical slip surface is established. It is shown that the dynamic adaptive genetic algorithm has better performance in finding optimal solution, quicker convergence than traditional algorithm as well as more reasonable results.