▎ 摘　　要

NOVELTY - Solid acid catalyst comprises a carbon-based carrier and a heteroatom loaded on the carbon-based carrier. The heteroatom is Group IIIA, Group VA and/or Group VIA elements, preferably boron, phosphorus and/or sulfur. The content of the heteroatom is 0.2-25 wt.%, preferably 1-15 wt.% in terms of simple substance, and the external specific surface area of the solid acid catalyst is 100-1000 m2.g-1, preferably 150-600 m2.g-1. USE - Used as solid acid catalyst. ADVANTAGE - The solid acid catalyst has higher external specific surface area and significantly improved acidity, and has higher catalytic performance for amide dehydration reaction. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: preparing the solid acid catalyst, comprising (S1) impregnating the carbon-based carrier source with a solution containing a heteroatom source and optionally a metal auxiliary agent source to obtain a solid acid catalyst precursor, and (S2) heat-treating the solid acid catalyst precursor under an inert atmosphere to prepare the solid acid catalyst; and use method of the solid acid catalyst in the field of preparation of nitrile compounds, preferably the amide compound dissolved in the organic solvent undergoes amide dehydration reaction under the action of the solid acid catalyst to generate the corresponding nitrile compound.