A touch sensor comprises first and second touch electrode stings. Each first touch electrode string comprises the same number of first touch electrodes in a first direction. Two adjacent first touch electrodes connect by a first or second conductive bridge. The resistance of the bridges is different to adjust the mutual capacitance such that the mutual capacitance or the difference of the mutual capacitance of the first touch electrode strings is the same or within a first predetermined range. Each second touch electrode string comprises the same number of second touch electrodes arranged in a second direction. Two adjacent second touch electrodes connect by a third or forth conductive bridge. The resistance of the bridges is different to adjust the mutual capacitance such that the mutual capacitance or the difference of the mutual capacitance of the second touch electrode strings is the same or within a second predetermined range.