This study investigates the differences in multimodal physiological signals between patients with Parkinson's disease (PD) and healthy individuals, focusing on how symptom fluctuations affect these signals in PD. A total of 35 PD patients and 30 healthy controls participated. The PD patients were further categorized into two groups: those with symptom fluctuations (SF) and those without (NSF). Multimodal physiological signals, including EEG, ECG, respiration, and pulse, were recorded in resting state. Features were extracted from these signals and analyzed using non-parametric statistical tests. The results showed that the SF group had significantly higher absolute power in the β bands in the frontal, parietal, and central regions, as well as increased δ band power in the parietal regions compared to the NSF group. Additionally, several time-domain characteristics of the ECG signal were significantly greater in the SF group. These findings suggest that symptom fluctuations may influence cortical activity and cardiac autonomic function in PD patients. While levodopa-based treatments can alleviate certain symptoms, they may not fully compensate for the functional alterations in brain activity. Further research is needed to explore the effects on other physiological systems.