A capacitive image sensor with noise reduction feature and a method operating the capacitive image sensor are provided. The capacitive image sensor includes: a number of capacitive sensing units, arranged in a form of an array, wherein each of the number of capacitive sensing units switches between three states: sensing state, idle state, and emitting state; a driving source, for providing a driving signal to an adjacent finger overlying the number of capacitive sensing units through the number of capacitive sensing units which are in the emitting state; a number of driving switches, each connected between one of the number of capacitive sensing units and the driving source; and a control and timing logic, connected to each of the number of driving switches, for controlling the state of each of the number of capacitive sensing units.