Composite soil nailing with pre-installed micro-piles is a cost-effective support system for deep excavation. The study simplifies the stability and deformation analysis methods for this system. By considering the pile stiffness relative to the soil, the global stability can be checked using passive resistance force. A formula for calculating pile width under lateral loading is provided. A straightforward method for stability analysis and displacement calculation of excavated pit walls is proposed, validated through comparison with finite element analysis and field measurements.