It is studied in this paper that in the manual SHS Welding, the amount of Ni added affects the quality of the welding, especially in view of the cracks. When the proportion of Ni is between 1.57％～7.86％, welding external appearances are in good condition. No welding cracks can be spotted. The strength of tension also reaches an optimum condition. When the proportion of Ni is 7.86％. there are internal cracks by the examination of machine. When the proportion of Ni is between 10.2% and 15.7%, there are obvious external and internal welding cracks and the strength of tension is also the lowest, about 193MPa.