Abstract: This paper concerns with the studies of gravitropic response of rhizoids of gametophytes 8 species ferns.The results indicate that,except the Selaginella tamariscina,the rhizoids of gametophytes of all the 7 species have gravitropic response at its initial stage,the gravitropic response of the rhizoids varies with the directions of light and shows negative phototropism.When the gametophytes get into platelet stage the effect of light on gravitropic response dicrease and gravity effect increase.Effect of light on gravitropic response of rhizoid is decided by whether the gametophyte have green assimilative tissue or not.Physiological mechanism of effect of light on gravitropic response of rhizoid and the abilities of gravitropic response of various fern rhizoids for plant systematical significance are discussed.