The invention provides a metal alloy XRF spectrometry utilizing a new sample preparation technology. The technology comprises the following steps: 1) acid dissolution: dissolving a metal alloy with inorganic acid; 2) precipitation: adjusting the above dissolved sample solution to be alkaline to precipitate elements to be measured, and filtering the precipitation with ashless filter paper; 3) calcination: placing the filtered filter residues together with the filter paper in a porcelain crucible calcined to a constant weight, conversing the filter residues into metal oxides through steps of drying, carbonization, ashing, calcination, etc, and calculating a weight of calcined filter residues; 4) sheet melting: preparing the above calcined filter residues into a sample sheet by a fusion sample preparation method for detection by an XRF spectrometer, and obtaining contents of elements to be measured in the metal alloy through conversion of obtained data. The invention enables the XRF spectrometry to be applied to detections of some special metal alloys which have a high melting point, a high hardness and is easily oxidized.