Abstract: This paper discussed the evolvement characteristics of sand bodies of the fourth coal bearing interval and its influence on No.13-1 coal-seam thickness in Huainan coal field.The distribution type of sand-mass of coal-seam floor varied greatly and its continuity is worse, which reflected the development characteristics of distributary channel in braid delta-plane. In coal-seam roof,distributary channel sedimentations mostly are vertical accretion, and the continuity of sand body evolvement is well.Closing to the period of coal-seam growth,the space distribution types of sandstones of floor and coal seam are adverse each other;however,in the early time of sand bodies growth, sand bodies flushed and influenced the nether coal-seam obviously.