A method of correcting a finish pattern dimension by using OPC when a design pattern is formed on a wafer, including selecting and determining a first design pattern included in the design pattern; acquiring a measurement value of a first finish pattern dimension when the first design pattern is formed on a wafer; determining a first calculation model by using the first finish pattern dimension; selecting and determining a second design pattern from the design pattern except for the first design pattern; performing first simulation by using the first calculation model, and calculating a second finish pattern dimension when the second design pattern is formed on a wafer; determining a second calculation model for performing second simulation which is faster than the first simulation, by using the first and second finish pattern dimensions; and performing the second simulation by using the second calculation model, and calculating a third finish pattern dimension of a third design pattern of the design pattern except for the first and second design patterns.