Background We recently reported an improvement of precuneus PET metabolism after EMDR therapy in military participants suffering from PTSD. Objective The aim of the present study was to investigate the metabolic changes of precuneus connectivity in these participants after such treatment. Method Fifteen participants with PTSD performed a brain 18F-FDG-PET sensitized by virtual reality exposure to war scenes, before and after EMDR treatment. Inter-regional correlation analysis was performed to study metabolic changes of precuneus connectivity through SPMT maps at whole-brain level (p < 0.005 for the voxel, p < 0.05 for the cluster). Results A decrease of connectivity was observed after EMDR between the precuneus and two significant bilateral clusters of the cerebellum (bilateral Crus I and VI cerebellar lobules, Tmax voxel of 5.8 and 5.3, and cluster size of 343 and 314 voxels, respectively). Moreover, higher cerebellar metabolism before treatment was associated with reduced clinical PTSD scores after EMDR (p = 0.03). Conclusions The posterior cerebellum and its metabolic connectivity with the precuneus are involved in the clinical efficiency of EMDR in PTSD.