An electronic expansion valve, comprising: a valve body having a tubular shape, wherein the valve body comprises a main body section, an extension section and a step section connecting the main body section and the extension section, and an inner diameter of the main body section is greater than an inner diameter of the extension section; a valve seat core having a tubular shape and having openings at two ends, wherein the valve seat core comprises a tubular body and a limiting step formed at one end of the tubular body, the tubular body penetrates through the extension section, the limiting step abuts against an inner wall of the step section and one end of the tubular body away from the limiting step extends out of the extension section; and an air outlet pipe, which is sleeved in the extension section and abuts against an outer wall of the step section, and a groove is defined by an inner wall of the air outlet pipe, the extension section, and an outer wall of the tubular body in a surrounding mode and configured for accommodating a welding ring; characterized in that, the tubular body comprises a middle portion and an edge portion, the middle portion is located between the limiting step and the edge portion, and the middle portion forms an interference fit with the extension section; and a length of the middle portion is less than a length of the extension section, and an outer diameter of the middle portion is greater than an outer diameter of the edge portion, so that a gap having an annular shape is defined between an inner wall of the extension section and an outer wall of the edge portion, and the gap communicates with the groove. a valve body having a tubular shape, wherein the valve body comprises a main body section, an extension section and a step section connecting the main body section and the extension section, and an inner diameter of the main body section is greater than an inner diameter of the extension section; a valve seat core having a tubular shape and having openings at two ends, wherein the valve seat core comprises a tubular body and a limiting step formed at one end of the tubular body, the tubular body penetrates through the extension section, the limiting step abuts against an inner wall of the step section and one end of the tubular body away from the limiting step extends out of the extension section; and an air outlet pipe, which is sleeved in the extension section and abuts against an outer wall of the step section, and a groove is defined by an inner wall of the air outlet pipe, the extension section, and an outer wall of the tubular body in a surrounding mode and configured for accommodating a welding ring; characterized in that, the tubular body comprises a middle portion and an edge portion, the middle portion is located between the limiting step and the edge portion, and the middle portion forms an interference fit with the extension section; and a length of the middle portion is less than a length of the extension section, and an outer diameter of the middle portion is greater than an outer diameter of the edge portion, so that a gap having an annular shape is defined between an inner wall of the extension section and an outer wall of the edge portion, and the gap communicates with the groove.