Deformation and even collapse may constantly happen in tunneling in soft rock, and the unsuitable treatment of them may induce operational risks. Tunneling in soft rock has always been the crux for tunnel construction, thus the mass engineers should grasp and study on the construction technology for safely tunneling in soft rock. In order to ensure safe tunnel construction and good tunnel quality in carbonaceous schist and sericiteschist interbedding, the deformation mechanism and its causes of sericiteschist under tunneling disturbance are systematically analyzed in this paper by orientation survey, theory analysis, numerical simulation and observation on site, based on the construction of Yanjia tunnel. Then, the deformation control technology for tunnels in complex soft rock is proposed and the key technologies of design, construction and support for tunnels in soft rock are drafted, via the above deformation mechanism analysis and the analysis of the relation between tunnel support and surrounding rock. The above study achievements have guaranteed the safe construction of Yanjia tunnel in soft rock, and may provide references for tunnels in similar soft rocks.