The invention relates to a composite flowing layer material for disposable sanitary articles and a preparation method thereof. The flowing layer consists of two layers of fiber webs, wherein the upper layer is a fiber web which is made of sheath-core bicomponent fiber with fiber length of between 38 and 60mm and fiber fineness of between 5 and 10 denier through or not through hydrophilic treatment; and the lower layer is a fiber web made of sheath-core bicomponent fiber with fiber length of between 38 and 60mm and fiber fineness of between 1.2 and 3 denier through hydrophilic treatment. The bicomponent fiber is arbitrary one of polyethylene/polypropylene or polyethylene/polyester. The preparation method is to prepare the upper fiber web and the lower fiber web with different structure designs respectively and overlap the two fiber webs to make the composite flowing layer material through heat composite reinforcement. The prepared flowing layer material is a non-woven material with high strength, strong fluid absorption capability, good flowing effect and good comfort, and can be widely applied to the field of disposable sanitary articles. The preparation has low energy consumption, does not use a chemical bonding agent, and does not have pollution.