Abstract: Dividing a nonlinear singularly perturbed system into the fast and slow subsystems and according to the assumption, a state feedback controller with asymptotic convergence is obtained for the fast subsystem. Then, based on Lyapunov function and the backstepping design technique, a state feedback controller for the slow subsystem is also constructed, which enables the closed-loop system to be internally stable for all bounded interference and satisfies the arbitrarily small bounded L2 gain from exogeneous interference input to its output. The strictly dissipative inequality for the whole system can be deduced through recursive method after getting that for the first subsystem. So, the design process of controller can be done without the solution to Hamilton-Jacobi equation. A simulation example shows the feasibility and effectiveness of the approach proposed.