A terminal seat comprises a first receiving portion, a second receiving portion and a joint portion formed between the two. The second receiving portion corresponds to the first receiving portion and has similar shapes. The joint portion formed between the first receiving portion and the second receiving portion has a smaller lateral cross-section and a smaller lengthwise cross-section than the first receiving portion and the second receiving portion so as to form an annular groove. A plurality of terminal seats can be assembled together by a fixing member. The fixing member crosses the annular groove and fastens the assembly of the plurality of terminal seats.