Abstract: Aiming at the problem of serious deformation phenomena such as two sides and floor heave occurring in the expanding soft rock roadway in the second panel area of 15^# coal of Chengzhuang Coal Mine, which is hard to meet the requirement of safe and efficient production. We carry out the research on the deformation mechanism of two sides and floor heave of the soft rock roadway in terms of the water-absorbing expansion of the mudstone and the stress concentration in the roadway. SEM test is used to reveal the micro mechanism of the expansion and deformation of the mudstone, and a mechanical model of floor deformation is established based on the theory of elasticity and plasticity. The mechanical model was established to analyze the mechanical mechanism of floor deformation and determine the maximum value of floor deformation. Based on this, the two sides and the floor deformation control technology scheme were proposed respectively, and industrial tests were carried out. The field monitoring data showed that: the two sides displacement of the roadway was less than 15 mm, and the floor heave was less than 100 mm after the support, which effectively controlled the deformation and damage of the roadway.