Microtechnologies have been vigorously developed recently. Micro products have been widely used in many fields, for instance, the sensors in electronic, medical, optical and automotive applications. Thermocouples, which are used for temperature measurement, are usually fabricated by utilizing the joining technology of argon arc welding. However, the weld bead is so big that the conductivity and repeatability of temperature signals would be degraded. Laser welding may fix the weld bead problem, but the cost of equipment is relatively high. This study is about butt-welding thin brass wire of 250 m by mean of micro discharge. At first a low temperature plasma torch is formed to ignited arc, then discharge happens to complete the welding. Argon is added at ambient atmosphere during the welding process. The joined interfaces and heat affect zone of the welding is examined by optical and scanning electronic microscopies. Tensile and hardness tests as well as the microscopy examination indicate that this technology is feasible for thin brass welding. The features of this technology include low cost, easy to maneuver, and applicable in industry. This CIMDW technology offer choice for the applications of micro discharge in the field of microtechnology.