Based on the construct detail, structural behavior of cellular voided slab was analyzed. Differential equilibrium equations and formulae of flexural and torsional stiffness of the cellular voided slabs were given. Solution of deflection of cellular voided slabs fixed supported by four edges were presented by numerical simulating method. Analysis and comparison by elastic finite element method on three group ensamples were carried out. The errors in numerical solutions to finite element method analysis results are little; the solution of deflection was applicable to solve cellular voided slabs fixed supported by four edges.