This study verified the relationship between fracture mechanics parameters(ΔK, ΔK$sub$eff/, K$sub$max/) and X-ray parameters (${alpha}$$sub$r/, B) for SG365 steel at elevated temperature up to 300$^{circ}C$. The fatigue crack propagation test were carried out and X-ray diffraction technique according to crack length direction was applied to fatigue fractured surface. The residual stress on the fracture surface was found to increase low ΔK region, reach to a maximum value at a certain value of K$sub$max/ or ΔK and then decrease. Residual stress were independent on stress ratio by arrangement of ΔK and half value breadth were independent by the arrangement of K$sub$max/. The equation of ${alpha}$$sub$r/ - ΔK was established by the experimental data. Therefore, tincture mechanics parameters could be estimated by the measurement of X-ray parameters.