Abstract: According to the site measured strata pressure information of the coal mining face in mining efflorescent oxygenized zone of coal seams in No.3 Coal Mine of China Coal Pingshuo Group Co. Ltd， the paper has discussed the obvious sectional variance features occurring in top coal and the overlying strata above mining face in efflorescent oxygenized zone, such as loose strata structure, low overburden rock strength, high plasticity property, strong hydrophilicity, serious sliming, and the obvious decrease of stability performance and bearing capacity. The mine strata-pressure behaviors of passing the efflorescent oxygenized zone of coal seams are mainly reflected in the following three aspects: periodic weighting distance shortened, both the maximum working resistance of hydraulic power support during roof pressurized period and the average working resistance during non-pressurized period increasing, and support dynamic load coefficient decreasing during passing the efflorescent oxygenized zone compared with outside the scope. The mechanism of the sectional variance in strata behaviors have been analyzed by using geological mechanics, from which the paper has shown that the geological incentive of the strata-pressure behaviors variability is the new type Soft Cushion effect caused by soft-broken surrounding rock，fractured and sliming rock mass and float coal auxiliary compression under the floor. The Soft Cushion effect will lead to lower working resistance of the supports. Then the characteristics of the support operation of working face have been analyzed and the adaptability of the powered supports has been assessed.

Key words: fully mechanized top coal caving, efflorescent oxygenized zone, characteristics of surrounding rock, the loading distribution of the powered support, strata behaviors