Vision plays an important role in living and learning for human, and its formation includes three processes: retinal photoelectric conversion, optic nerve transmission, and visual cortex perception. According to statistics, there are more than 450 million people with various vision problems in the world. Visual impairment like blindness will significantly reduce the quality of human life. Visually impaired patients usually have no or weak vision due to a problem in one of the processes, which provides possibilities to recover part of the vision of with the help of artificial visual aid systems for most visually impaired patients. This article reviews the development status, limitations and outlooks of state-of-the-art various artificial visual aid systems. To date, there are three kinds of visual aid systems for different vision impairment situations. For patients with retinopathy or lesions in lens, vitreous, cornea, etc., the remaining part of the visual pathway is still functional, so the electrode array or photoelectric array can be implanted into the retinal area, and plays a role in retina to generate electric signals to stimulate the optic nerve, which transmits electrical signals with visual information to the brain. For visually impaired patients whose visual cortex is functional normally, the electrode array can also be applied to the brain's visual cortex to input electrical signals with visual information directly. In addition, external devices using artificial intelligence to convert vision into voice commands, tactile array coding, etc., can help blind patients obtain environmental information. The implantable visual aid systems mainly face the risk of biological rejection and infection, and their resolution of vision restoration is limited by the electrode size. More complete visual aid electronic devices and systems that can be worn or implanted need to be developed to benefit a large number of patients with visual dysfunction. As a result, here new ideas for implanting devices and extracorporeal aid system are proposed to provide some valuable references for this field.