A photoacoustic detector, a photoacoustic board and a detector using the photoacoustic board are provided. The photoacoustic detector includes a X-ray transmitter, a X-ray receiver, a light module and an ultrasonic module. The X-ray transmitter is configured to transmit a X-ray to irradiate the object. The X-ray receiver is configured to receive an image beam generated after the object is irradiated by the X-ray. The light module is configured to provide light for illuminating the object to generate a first sonic wave signal. The sonic module is configured to receive the first sonic wave signal, transmit an sonic wave toward the object, and receive a second sonic wave signal generated after the object is interacted with the sonic wave. Therefore, a X-ray image, an ultrasonic image and a photoacoustic image are obtained via the photoacoustic detector.