There is a lack of a safe and effective technology to monitor intracranial pressure accurately and non‐destructively. In this paper, the relationship between reduced scattering coefficient and intracranial pressure in clinical patients under different brain edema states was studied. First, the brain edema MC simulation model was constructed based on different types of brain edema. The results laid a foundation for clinical ICP detection. Second, the changes of ICP and reduced scattering coefficient caused by brain edema were studied in clinical application. It was found that when the patient developed brain edema, the reduced scattering coefficient and ICP showed corresponding changes. Finally, the mathematical model of invasive ICP and reduced scattering coefficient was established. It was found that the sensitivity of 834 nm light to brain tissue changes was higher than that of 692 nm light, which could be used to reflect the changes of brain tissue physiological state.