Verifiable sufficient conditions for parameter convergence of an adaptive fully linearizable system with unknown parameters, including those affine with the control input, are provided. The adaptive control in C. T. Chen (1986) has solved the tracking problem for a wider class of systems. However, parameter convergence so far cannot be verified a priori. By taking advantages of the obtained asymptotic tracking stability and the vanishing time derivatives of the estimated parameters, we found it can indeed be checked beforehand provided some mild assumptions are satisfied. Numerical examples for illustrating the main results are given in the final.