In this paper, we will propose an evaluation method for reliability on phase-shifting methods. Environmental noises (e.g. vibration, air turbulence) affect quality of 3D measurement results in phase-shifting interferometry. Proposed method computes the score relating to quality of phase images. The correlation between the computed scores and ripple errors (surface roughness) was revealed by the experiments with dent sample made of silicon. As a result, the correlation with proposed method are higher than conventional ones. Hence, the qualities of measured phases can be ensured by the proposed method.