Parkinson’s Disease (PD), commonly seen in adults over the age of 65, is the second most common neurodegenerative disorder. Researchers are working towards developing a highly sensitive biosensor for diagnosing PD. Diamond-gold nanomaterials hybrid on interdigitated parallel microelectrode (IDME) biosensor is introduced for diagnosing PD. Alpha-synuclein contributes to the progression of PD, it was used as a target to diagnose PD, and aptamer was immobilized as a capture molecule. For higher aptamer immobilization, IDME was modified by diamond nanomaterial through 1,1′-Carbonyldiimidazole linker and then aptamer (with or without gold nanoparticle conjugated) was attached on the diamond by using an amine-linker. This aptamer immobilized surfaces detect the alpha-synuclein by aptamer-antibody sandwich and lowers the detection limit to 1 aM [y = 1.5679x − 1.7834; R² = 0.9904] in the buffer sample and 10 aM in an artificial cerebrospinal fluid on a linear regression from 1 aM until 1 nM. In addition, control performances with DJ-1, PARK-1, and complementary anti-alpha-synuclein aptamer failed to increase the current responses confirm the specific detection of alpha-synuclein. This diamond modified IDME quantifies the alpha-synuclein at its lower level and helps to diagnose PD.