The deep area of photocuring system can't be radiated by light, which usually results in low conversion rate. Several commonly used methods to solve the problem are described, including conventionally increasing monomer function, adding crosslinking agents, and improving photoinitiator system. In addition, some new methods such as up/down-conversion luminescence, visible/infrared photocuring and two-photon curing are introduced. The advantages and disadvantages of each method are summarized to provide direction for future scientific research.