A new type of combination of three experimental and numerical computation procedures for two-dimensional stress analysis is presented, 1) photoelastic isochromatics (σ1-σ2), 2) digital computation of Laplace's equation ∇∇2 (σ1+σ2) =0, 3) measurement of thickness change Δt= (σ1+σ2) νt/E of the model plate along the boundaries subjected to concentrated or distributed loads. The whole Laplace's field of (σ1+σ2) is computed by finite difference iterative harmonization procedure with the input boundary conditions obtained by the measurement of thickness change of the plate very accurately using a highly developed Digital Mu-Checker (M-311; Mitutoyo, up to the resolution of 0.0001mm). As the example, this procedure is applied to a circular disk under diametral concentrated loads. The results obtained are found to be satisfactory.