Cognitive impairment is a multifactorial neurodegenerative disease caused by the complex interaction between genetic and environmental factors. Previous studies found that spatial disorientation is a crucial symptom of cognitive impairment. Most of the previous studies focused on patients with early, middle, or late stages of dementia. However, there are few studies on spatial disorientation in patients with initial mild cognitive impairment. Therefore, this study would construct complementary spatial disorientation tests for the real environment and virtual reality to effectively evaluate the ability to create spatial knowledge, including Landmarks, routes and maps formed by spatial orientation in patients with initial mild cognitive impairment. Then, a cerebral cortex degeneration assessment model will be formulated. The results showed that for subjects suspected of initial mild cognitive impairment, the analysis results of the cerebral cortex degeneration assessment model were significantly different from those of normal subjects. Subjects suspected of initial mild cognitive impairment had a relatively significant sign of brain cell degeneration. The accuracy of head direction in virtual environment (H1) was significant index on the head direction cells degeneration. The landmark recognition accuracy in real environment (G2) was significant index on the grid cells degeneration. The error pathfinding length in real environment (B1) and pathfinding time in virtual environment(B6) were significant index on the boundary cells degeneration. The pathfinding idle time in allotheticity in virtual environment (P6) was significant index on the place cells degeneration.