In the application of brazed diamond tools, residual stress caused by differences in materials properties is an important factor in obtaining good brazing quality. The residual stress in diamond/steel brazed joint is studied by means of finite element method and Raman spectroscopy in this paper. The comparison between the results from the simulations and the measurements shows that a good agreement has been reached. Tensile stress concentration at the diamond edge near interface was observed. High residual stress concentration may cause cracks in diamond. Actually, cracks in diamond caused by brazing residual stress after were observed. The stress concentration of the joint must be reduced to obtain good brazed joint. The change of brazing atmosphere or to adopt the soft brazing alloy will reduce the stress concentration.