A coordinate detection input system includes two first elongated electric conductors with an insulation grounding device respectively, a control circuit and two elongated electric conductors with another insulation grounding device respectively. The two elongated electric conductors are disposed correspond to X-coordinate and Y-coordinate of the input system. The control circuit further includes a microprocessor, a field induced voltage transducer, an analog/digital converter and a signal transmission device. The elongated electric conductors are electrically connected to the microprocessor to induce electromagnetic fields sequentially every time after a zero checking has been done by the microprocessor. The field induced voltage transducer induces voltage in the magnetic field once the pulse current is operated to pass through any one of the electric conductors. The analog/digital converter transforms the induced voltages as coordinates and position of the field induced voltage transducer can be figured out accordingly.