For the interior slab, the edge slab and the corner slab of cast-in-situ reinforced concrete two-way slab-and-beam floor system, it was carried out the static loading test under uniformly distributed load respectively, and metered the beams and slabs deflections of three slabs.Through considering the influence of boundary supporting condition, the deflection calculation formulas of three typical slabs of two-way slab were established, and comparing the deflection values calculated by the formulas to the experimental results.The results showed that under uniformly distributed load the two-way slab deflections at the midspan section calculated by elastic thin plate theory differed significantly from the test results, and the deflection values obtained by the deflection calculation formulas in this paper matched well with the test results.