The maximum power point of offshore floating photovoltaic(FPV) panels exhibits continuous variation due to wave motion, experiences abrupt shifts under extreme sea conditions, and displays multiple power peaks in the presence of partial shading, thereby increasing the complexity of power tracking. This paper first analyzes the phenomenon of misjudgment caused by power fluctuates continuously in the traditional perturbation and observation (P&O) method under continuously changing light intensity. To address this issue, a variable-step-size P&O method based on two-point power prediction is proposed, which reduces power losses due to misjudgment and improves the response speed and stability of the system. Secondly, a virtual impedance characteristic method is proposed to initially locate the maximum power point voltage value. This approach addresses maximum power point jumps under extreme sea conditions and can also incorporate a global search mechanism into the improved P&O method to effectively manage partial shading situations. Finally, the proposed algorithm is validated through simulation. The simulation results align with the theoretical analysis, confirming the effectiveness of the algorithm.