Objective　To research the change rules and clinical significance of area and fractional anisotropy (FA) in cerebral peduncles among patients with silent lacunar infarct in pyramidal tract  Methods: 54 patients with silent lacunar infarct in pyramidal tract diagnosed by MRI and 105 healthy adults were selected as study subjects. The cerebral peduncle area and FA of 54 patients were divided into two groups according to injured side of cerebral peduncle: injured side group and uninjured side group, the area and FA of two groups were compared with the control group, as well, the cerebral peduncle area and FA asymmentry ratio of lacunar infarct group was compared with that of the control group.　Results　The cerebral peduncle areas of 54 patients with silent lacunar infarct in pyramidal tract were smaller than that of control group(Left F=17.104 ，P=0.000，Right F=12.581,P=0.000). There was no difference of cerebral peduncle FA between lacunar infarct group and control group (Left P=0.894, Right P=0.968), and there was no difference of area and FA between left and right cerebral peduncle in lacunar infarct group (t=0.254 P=0.800,t=0.268 P=0.790). There was no difference of cerebral peduncle area and FA asymmentry ratio between observed group and control group (t=0.114 P=0.267,t=1.463 P=0.175.　Conclusions　The lesion of silent lucunar infarct in pyramidal tract can't lead to area and FA changes of cerebral peduncle in all, there is no affect on area and FA changes of cerebral peduncle caused by Wallerian degeneration after cerebral infarction.