Abstract: Composite soil nailing with pre-installed micro-piles is a type of economical and effective support system for deep excavation. The study on its design analysis method is however far behind current engineering practice. In this paper, the constitution and working performance of this type of composite soil nailing is first discussed, then the calculation methods for its global stability and deformation are studied and simplified calculation methods have been proposed. For the global stability checking, it is suggested to use the passive resistance force on a maximum characteristic-length of 2.5 times for the pile, which reflects the pile stiffness relative to the soil, to consider the contribution of the micro-pile to the global stability. A formula for the calculation width of piles under lateral loading is also given. Thereafter, a relatively simple method has been put forward for the stability analysis, which is proved to be reasonable through comparison with finite element calculation and some analysis of practical engineering projects. For the calculation of displacements of the excavated pit wall, a relatively simple and clear method has been proposed based on the incremental calculation method and the theory of a beam on elastic foundation by the careful consideration for the deformation mechanism of this type of supporting system. The calculation model, together with the load and stiffness parameter determination method, is established, and the validity of the method is also proved by the comparison with finite element analysis and field measurements.