Femtosecond (femtosecond), also known as femtosecond, or fs for short, is a unit of measurement to measure the length of time, and femtosecond lasers are the shortest pulse technology available to mankind under laboratory conditions. Femtosecond lasers, which emit a huge amount of power in an instant that is greater than the total power generated worldwide, are already being used, and scientists predict that femtosecond lasers will play an important role in generating new energy sources for the next century. Femtosecond laser is a laser that operates as a pulse, 1 femtosecond = 10-15 seconds. Femtosecond laser technology is a cutting-edge technology in the field of ophthalmology, utilizing its short pulses, high instantaneous power and fine positioning to focus on an ultra-fine spatial area smaller than the diameter of a hair, allowing for more precise cutting of corneal tissue. The technology makes the corneal refractive surgery into the knifeless era, the current femtosecond laser for corneal refractive surgery such as myopia, hyperopia, astigmatism more advanced femtosecond machine can do full femtosecond surgery and presbyopia correction, but also corneal transplantation, cataract tear capsule nucleus, glaucoma treatment, can be said to have epoch-making significance in the development of ophthalmology.