Parkinson's sickness with mellow intellectual debilitation (PD-MCI) or dementia (PDD) has been demonstrated to be connected with low quality of life (QoL). The relationship between explicit subjective spaces and QoL is less clear. Objective: To decide how the subjective areas influence QoL in various psychological states in PD. Techniques: We enlisted 600 PD patients, incorporating 185 PD patients with typical discernment (PD-NC), 336 PD-MCI patients, and 79 PDD patients. All patients experienced a scale-based appraisal (PDQ-39) for QoL, just as clinical assessments and neuropsychological tests. Results: Compared to the PD-NC gathering, QoL turned out to be increasingly weakened in the PD-MCI and PDD gatherings. The summed up direct model uncovered that no neuropsychological test was fundamentally connected with QoL in PD-NC gathering; neuropsychological tests in consideration and language spaces were essentially connected with QoL in PD-MCI patients; neuropsychological tests in memory and language areas were altogether connected with QoL in PDD patients. Ends: Cognitive spaces contribute distinctively to QoL in PD. These discoveries may provoke clinicians to target explicit subjective areas for improving QoL in PD patients.