The invention relates to a stainless steel pipe and a preparation system and a processing method thereof. The method comprises the following steps of 1, soaking the stainless steel pipe in water; 2, taking the stainless steel pipe out of water, abutting one end of the stainless steel pipe against a left pipe base, and fixing the inner end at one end of the stainless steel pipe by adjusting the left pipe base; 3, controlling a right pipe seat to abut against the other end of the stainless steel pipe, and fixing the inner end at the other end of the stainless steel pipe; 4, grinding and polishing the pipe surface of the stainless steel pipe; and 5, enabling a rotary driver to drive the left pipe base and a sliding rail assembly to work, driving the stainless steel pipe fixed between the leftpipe base and the right pipe base to rotate, and grinding and polishing different positions of the pipe face of the stainless steel pipe through a polishing assembly. According to the present invention, the stainless steel pipes with different diameters can be effectively clamped and fixed, a weld beading generated after the stainless steel pipes are welded is polished and ground, so that the weld beading is eliminated, and the quality of the stainless steel pipes is improved.