Abstract: The north part of a bentonite deposit is overlaid in Liaoning Province.The exposure strata in the deposit,as slight dipping angle monoclinal structure,are Lower Cretaceous Yixian formation volcanicsediment rocks.There are 2 bedding ore body in pyroclastic rocks in the overlaid area,whose occurrence are same to the tuff wall rocks.The ore is remnant tuff texture,and contain a few of volcano matters.The author infers the deposit is a andesitic tuff sedimenthydrolysis type bentonite deposit.According CEC,XRD,colloid index and swelling volume analysis,the ore is Cabentonite,and has wide application prospect.

Key words: bentonite deposit,geology character,physical and chemical properties