Marine active fault exploration and paleoearthquake research are still a gap in China. The paper gives a review on major research methods and new progress made abroad, including submarine survey boat, seismic reflection and acoustic reflection. Through detailed studies of offset history of 10 ka to 30 ka, it is possible to determine paleoearthquake recurrent intervals and elapsed time since last major earthquake. It is suggested that active fault exploration can be carried out by acoustic exploring method in large earthquake region of Bohai Sea. Paleoearthquake activity history can be revealed and earthquake risk in the future can be predicted. Marine active fault exploration and paleoearthquake research are still a gap in China. The paper gives a review on major research methods and new progress made abroad, including submarine survey boat, seismic reflection and acoustic reflection. 30 ka, it is possible to determine paleoearthquake recurrent intervals and elapsed time since last major earthquake. It is suggested that active fault exploration can be carried by by acoustic exploring method in large earthquake region of Bohai Sea. Paleoearthquake activity history can be revealed and earthquake risk in the future can be predicted.