Abstract: Because of low strength of coal seam and its own roof and floor，the mining of“three soft” coal seam is easy to cause strong mine pressure phenomenon，which leads to severe overburden movement. In order to study the movement law of overlying strata in the mining process of“three soft”coal seam，the 3505 working face of“three soft”coal seam in Shanyang Coal Mine is taken as the research object，and the subsidence and caving law of overlying strata under the mining condition of“three soft”coal seam is obtained by means of similar simulation test and numerical simulation calculation. At the same time，based on distributed optical fiber，the strain law of overburden rock under the condition of“three soft”coal seam mining is studied，and it is concluded that there is a positive correlation between overburden rock failure and optical fiber strain，which confirms the relationship between overburden rock collapse and strain after working face mining. The results show that the“three soft”coal seam in the early stage of mining，the over⁃ lying rock movement is severe，and the degree of damage is higher than that in the middle stage of mining and the full mining period. Both the similarity simulation and the numerical simulation show that in the pro⁃ cess of advancing the working face to 0~120 cm，the weighting step of the overburden rock is short，and the subsidence of the overburden rock is large，showing severe overburden rock collapse and subsidence. At the same time，the distributed optical fiber has a high strain peak at 0~120 cm，and the corresponding mining process has high pressure strength and complete fracture development. When mining 120~260 cm， the strain curve gradually decreases and tends to be stable，which confirms the failure of the overburden mining stage.

Key words: “three soft”coal seam, numerical simulation, similar simulation, optical fiber