The invention relates to the field of sensors, in particular to an outer clamping type current sensor and a manufacturing method thereof and an auxiliary manufacturing tool. The manufacturing method of the outer clamping type current sensor comprises the following steps: 1) butting two semi-annular frameworks of the outer clamping type current sensor into a circle through an auxiliary manufacturing tool, 2) mounting the two butted semi-annular frameworks on a winding machine, and respectively winding coils on the two semi-annular frameworks; and 3) after winding is completed, disassembling theauxiliary manufacturing tool, so that the two semi-annular frameworks with the coils are separated, and then the outer clamping type current sensor is assembled with other parts. The invention discloses a manufacturing method of an external clamping type current sensor. According to the manufacturing method of the outer clamping type current sensor, the two frameworks are in butt joint to form acircle through the auxiliary manufacturing tool, then the two frameworks are wound, the winding uniformity degree is improved, meanwhile, the machining efficiency is improved, and the problem that themachining efficiency is low due to the fact that an existing winding method of the outer clamping type current sensor is complex is solved.