To address the problems of traditional frequency tracking, such as falling into a local optimum, oscillation near the optimal point, and contradiction between tracking speed and tracking accuracy, an improved perturb–observe method based on component drift parametric scanning is proposed. An inductive contactless power transmission system with LCC/S third-order compensation topology is employed as the research object. First, the relationships between the output voltage and frequency under component drift parametric scanning are given by theoretical deduction and calculation. Then, a reasonable working frequency band is intercepted, and the improved perturb–observe method (including start, end, step, and anti-death cycle judgement) is used to track the optimal working state adaptively. Finally, the correctness of the proposed theory and method was verified by simulations and physical experiments.