Cold working a hole decreases tendency of fatigue crack near the hole to initiate or growth. It is due to creation some compressive tangential residual stresses around the hole. Determination of mentioned residual stresses with a non-destructive, simple and non-expensive method is the key step in design process of holed components. In this article, residual stresses have been determined by mounting some strain gages around the hole and in fact surface strains during cold working process have been introduced as a feature for residual stress field. Delineation the numbers of needed strain gages and also proper place for mounting them around the cold worked hole is the main object of this research. Results have a good agreement with test result of cold working on specimens made of Al2024. According to the results, mounting two strain gages at same radius in opposite side of hole edge; which one in radial and another in tangentially direction; is needed for determining the residual stress field. Also, strain gages should be mounted in elastic zone. Mounting the gages in plastic zone led to have errors and unreliable results.