Parkinson's disease (PD) is a neurodegenerative movement disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra and depletion of dopamine in the striatum, which lead to pathological and clinical abnormalities. Increasing evidence has demonstrated that inflammation is the fundamental process contributing to neuron death in PD. Neuroinflammation, which is characterized by activated microglia and infiltrating T cells at sites of neuronal injury, is a prominent contributor to the pathogenesis of progressive PD. Microglia play a critical role in forming a self-propelling cycle leading to sustained chronic neuroinflammation and driving the progressive neurodegeneration in PD. This activation depends heavily on the respiratory burst within the microglia, which in turn regulates a number of downstream pro-inflammatory activities. On the other hand, the adaptive immune responses, most notably T cells, are now emerging as important components of the inflammatory response that contribute to the pathogenesis of PD. This review paper focus on the understanding of the inflammatory etiology of PD, as well as the molecular signaling involved in this inflammatory response, with the aim to provide more effective treatments to slow down or halt the progression of chronic inflammation-induced CNS disorders, such as PD.