A temper bead welding procedure without postweld heat treatment is performed at the carbon steel testing coupon to obtain as-weld deposited metal using the low alloy steel wire which is usually employed for the reactor pressure vessel. The low cycle fatigue test and high cycle fatigue test of as-weld deposited metal at room temperature are performed according to ASTM E466 and ASTM E606

and the low cycle fatigue curve and high cycle fatigue curve are constructed by means of Coffin-Mansion Equation and Tri-parametric Equation.Meanwhile

low cycle fatigue curve and high cycle fatigue curve are further revised according to the correction method recom-mended in RCC-M code which is employed for nuclear power equipment design. In addition

the revised S-N curves are compared with the design fatigue curve of low alloy steel specified in RCC-M code. The result shows that the revised SN curve（low cycle fatigue） of deposited metal basically coincides with the design curve（low cycle fatigue） specified in RCC-M code

the revised S-N curve（high cycle fatigue） of deposited metal is above the design curve（high cycle fatigue） specified in RCC-M code.