【Abstract】 Objective To investigate the ability of decision making under ambiguity condition in patients with emotional apathy for Parkinson′s disease. Methods 58 PD patients were included in the neurology ward of the first affiliated hospital of USTC From January 2015 to January 2017. According to the emotional apathy scale, PD patients were divided into PD group (30 cases) and nonAP group (28 cases). At the same time, 30 age and gender matched healthy controls were included in the present study．Neuropsychological background test and Iowa game task (IGT) experimental paradigm were used to evaluate the cognitive function and decisionmaking function under ambiguity, and the differences of the three groups in the above measurement scores were compared. Results Compared with the healthy control group, the MOCA score and frontal lobe fluency of AP group and non AP group decreased significantly, while the HAMA score increased significantly (P＜0.05). The scores of HAMD in AP group were higher than those in healthy control group and non AP group. The scores of digit span reverse back and recognition memory were lower than those in HC group and non AP group. The scores of delayed memory in AP group were lower than those in HC group(P＜0.05). The total score of IGT task in AP group and non AP group was lower than that in healthy control group, and the total score of decisionmaking ability in AP group was lower than that in non AP group and healthy control group (P＜0.05). Conclusion The decisionmaking function of PD patients with emotional apathy is impaired obviously under the condition of uncertain risk, and the mechanism may be related to the functional impairment of ventromedial prefrontal cortex loop.