Abstract: A comprehensive study was carried out on portable XRD residual stress analyzers using single exposure cosα method promoted in recent years, and the principles were explained in detail. Algorithms of 2-dimensional and 3-dimensional stress states were analyzed. The applicability of the method was evaluated when there were nonlinear relationships in materials such as coarse crystal, curved surface, texture and stress gradient. Measurement results using cosα and sin²ψ methods according to international and domestic standards were compared, and conveniences of instrument focusing and replacement of collimator and X-tubes were investigated. A scientific and objective basis to evaluate merits, demerits and applicability of the stress analyzer using cosα method was provided.