Abstract: This paper investigates the problem of global adaptive stabilization by output-feedback for a class of uncertain nonlinear systems. Due to the uncertain control coefficients and unknown linear growth rate, this problem is much complicated and quite difficult to solve. In this paper, a novel dynamic gain updated on-line is introduced, and based on this, high-gain K-filters are proposed to reconstruct the system states. Then, motivated by the universal control method, the backstepping design approach is developed for the adaptive output-feedback stabilizing controller. It is shown that the global stability of the closed-loop system can be guaranteed by the appropriate choice of the design parameters. A simulation example is also provided to illustrate the correctness of the theoretical results.