Abstract: A nonlinear integral finite-time control approach is proposed in this paper to address the control issue for a family of single-input single-output (SISO) affine nonlinear systems with matched disturbances. The system manifold is transformed via feedback linearization, converting the nonlinear system into a linear form, and the finite-time stability of the closed-loop system is rigorously proven using the Lyapunov method. To overcome the difficulty of frequency-domain analysis for nonlinear systems, a linear parameter-varying (LPV) framework is introduced to analyze the closed-loop system. By treating the nonlinear system states as time-varying parameters, a quasi-linear parameter-dependent model is constructed, and a generalized frequency response is derived in the complex plane, revealing the dynamic behavior of the system poles. Based on this, the dynamic motion patterns of the system poles during state convergence are explored via generalized root locus analysis, which can be directly utilized for visual assessment and guidance in tuning control gains. Finally, simulations are conducted on the DC-DC converter. With the parameters tuned based on the aforementioned frequency-domain analysis, the system achieves improved robustness metrics. For the proposed method, the integral absolute error of output voltage tracking under matched disturbances is 14.31, and the integral absolute error of disturbance rejection is 2.70. The results demonstrate that the proposed method can effectively suppress matched disturbances and reduce the settling time.