In this paper, focusing on the existence of uncertainty in nonlinear system, robust analysis of right coprime factorization structure will be accomplished based on a time-varying Bezout Identity. To start with, an operator working on the quasi-state space of the target plant will be designed as a reflection of uncertainty. Then, the time-varying Bezout Identity could be formulated to stabilize the uncertain plant. In addition, for more general application, a novel robust condition will be proposed, which is analyzed subsequently and proved to be superior over previous methods. Simulation tests are carried out and exhibited results imply the effectiveness of proposed approach.