Abstract: As a form of discontinuous surface damage caused by coal mining，fissures are influenced by mining intensity，stratigraphic structure，surface properties，and other factors.Based on Houcun region of Ruhe as an example，the experimental study on sandy loam fissures development characteristics under the influence of underground mining are carried out.The result of soil physical mechanical properties test and theoretical calculation show that the structure of sandy loam is loose with low cohesive force and abundant joints，resulting that the sandy loam is more likely to produce mining fissures than clay，and the limit depth of fissures in sandy loam is greater than that in clay.At the same time，the reasons that the shapes of fissures in plane are strings of beads and that in depth is in mouth shapes are analyzed.The result will provide technical support for mining and ground buildings protection in similar geological and mining conditions.

Key words: Sandy loam, Fissure, Plane distribution, Limit depth