A laser crystallization measuring apparatus including a spectrometer configured to measure actual data of a spectrum of an actual polycrystalline silicon layer crystallized by a laser crystallization device, and a simulation device that is connected to the spectrometer and is configured to determine simulation data of a spectrum of a virtual polycrystalline silicon layer according to a shape of a virtual protrusion formed in the virtual polycrystalline silicon layer, wherein a shape of an actual protrusion formed in the actual polycrystalline silicon layer is determined by using final data determined by selecting simulation data that is approximate to the actual data.