The wavefront reconstructing is bound to be influenced by the subaperture partition manner based on certain deformable mirror in adaptive optics. This paper takes account of this issue. Zonal wavefront reconstructing model is adopted, the least-squares solution is applied, and the condition number of wavefront-reconstruction-matrix is used to estimate how its morbidity is. The computer simulation results indicate that the morbidity is mainly influenced by the number of subapertures; appropriate manner of subaperture partition may greatly decrease the degree of the morbidity.