The invention discloses an alloy composition determination method and device. The device comprises a detection module, a selection module and a determination module, wherein the detection module is used for detecting an alloy component to be detected to obtain the alloy designation of the alloy component to be detected and the spectral line intensity of elements of the alloy component to be detected, the selection module is connected with the detection module and used for selecting an alloy designation database in a preset calibration curve database according to the alloy designation, and thedetermination module is connected with the selection module and used for determining the content of the elements of the alloy component to be detected according to an XRF (X-ray fluorescence) spectrumanalysis calibration curve of each element in the alloy designation database and the spectral line intensity of the elements. The technical problems of long alloy composition detection time and low detection efficiency in related technologies are solved.