The present disclosure relates to an electrode strip, a sensor strip and a system thereof. The electrode strip includes a substrate, an electrode layer, an insulation layer and a cover. The electrode layer is disposed on the substrate. The electrode layer includes a first electrode set and a second electrode set. The insulation layer includes a groove, a first protrusion and a second protrusion. The first protrusion and the second protrusion divide the groove into two reactive areas such as a first reactive area and a second reactive area. The cover includes a vent-hole connecting to the groove, and the cover is disposed on the insulation layer.