Objective To observe the abnormal expression of transthyretin in serum and vitreous of high myopia patients. Methods 116 patients (50 males and 66 females) with high myopia, diagnosed by retinoscopic reflex, slit-lamp microscope, indirect ophthalmoscope and Iol-Master, were enrolled. The patients had an average age of (49.7plusmn;12.3) years and average diopter of (-10plusmn;4.2) D. The control group had 86 healthy individuals (42 males and 44 females) with an average age of (48.5plusmn;10.5) years. According to the findings of indirect ophthalmoscope and optical coherence tomography (OCT) examination, the patients were classified as foveal detachment, macular hole, choroidal neovascularization, epimacular membrane, retinal scar and no significant pathological changes. 2 ml peripheral blood samples were taken from all the subjects. The vitreous samples of high myopia patients with foveal detachment and macular hole (20 patients, 20 eyes) were collected before pars plana vitrectomy. LTQ-MASS was performed on 16 serum samples of patients and 16 control serum samples. Western blot and enzyme linked immunosorbent assay (ELISA) were used to detect serum transthyretin expression in high myopia groups（n=100）and control group (n=80). Vitreous samples (n=20) and corresponding serum samples were further analyzed by ELISA. Meanwhile, the relationship between visual acuity after surgery and transthyretin expression level in vitreous were analyzed. Results LTQ-MASS detected 4 proteins differentially expressed in the serum of patients and control group, transthyretin was the most significantly increased protein in high myopia patients. Western blot validated that serum transthyretin of high myopia group was much higher than that of the control group (t=3.68, P＜0.05). High myopia patients with macular hole and macular detachment had much higher serum and vitreous transthyretin than that of control group (F=9.28，P＜0.01). Patients with higher vitreous transthyretin had better postoperative visual acuity. Conclusions The transthyretin level increases significantly in serum and vitreous of high myopia patients, and it correlated with ocular pathologies and visual outcomes.