Abstract: AbstractA residual stress reference material of iron block for X-ray residual stress tester calibration was developed. The uniformity and stability of the residual stress reference material of iron block were investigated. The residual stress of the iron block reference material was jointly determined by eight laboratories using X-ray residual stress testers with calibrated and traceable angles, and the uncertainty of the reference material was evaluated. The results showed that the reference material had good uniformity and stability. The residual stress standard value for the iron block reference material was 14.9 MPa, and its expanded uncertainty was 3.4 MPa (k=2). The residual stress reference material of iron block has extensive and important application value, which can meet the calibration needs of X-ray residual stress tester, and provides equivalent, consistent, accurate and reliable technical support for residual stress measurement in scientific research, production and trade activities in China, filling the domestic gap.