A pixel sensing device, an organic light emitting display device and a pixel compensation method thereof are disclosed. The pixel sensing device comprises a plurality of current integrators for sensing driving characteristics of pixels. Each current integrator comprises: an operational amplifier equipped with an inverting input terminal to which a first input voltage is applied according to a pixel current of the pixels, a non-inverting input terminal to which a second input voltage is applied according to the pixel current, and an output terminal through which an integral voltage corresponding to the pixel current is output; and a feedback capacitor connected between the inverting input terminal and the output terminal. The operational amplifier comprises: a pre-amplifying unit for lowering an amplifier input gain and being equipped with the inverting and non-inverting input terminals; and two gain amplifying units for receiving an output of the pre-amplifying unit and for making an amplifier output gain higher than the amplifier input gain.