Concrete waste, a global problem. Only in China,2.4 billion tons of concrete waste is tore down each year. Concrete is a kind of building material with the largest consumption at present, which is widely used in water conservancy, hydropower, transportation, industry and civil buildings. However, concrete is typical brittle material, which is easy to crack when the tensile stress exceeds the tensile limit. Concrete is susceptible to temperature differences, wind, sun and uneven ground settlement, resulting in shrinkage, cracks and other phenomena, thus accelerating the invasion of water, oxygen and corrosive media, resulting in further deterioration of the concrete damage and internal steel corrosion. Finally the building structure will collapse. These characteristics of concrete make the life of concrete buildings not exceed 50 years in most cases. On the one hand, it causes negative economic effects. On the other hand, as non-biodegradable material, concrete generates a large amount of construction waste, which seriously affects the ecological environment. Therefore, it is urgent to solve the problem of concrete cracking and prolong the life of concrete buildings.We designed a light-repairing concrete particle, which is composed of outer photodegradable material and inner repair agent, mixed with the concrete and used to build the wall. Before the concrete cracks, the photodegradable material stays inside the wall and does not react, maintaining the original structure. When the concrete cracks, light enters the crack and particles near the crack receive the sunlight. The photodegradable material in the skin begins to break down, and the repair agent inside is released, automatically filling the wall crack.Through this particle, once the concrete cracks, the repair agent immediately begin to repair, which greatly enhance the stability of the concrete structure and prolong the life of the concrete building.To some extent, this method can restore and improve the performance of concrete.