The invention provides a method and equipment for preparing hydrogen fluoride from fluosilicic acid. The method comprises the following steps: concentrated fluosilicic acid and concentrated sulfuric acid are mixed, after reaction, mixed gas of silicon tetrafluoride and hydrogen fluoride and dilute sulfuric acid are obtained; washing and condensation are carried out; silicon tetrafluoride gas is added into dilute fluosilicic acid, and silica solid and concentrated fluosilicic acid clear liquid are obtained. The equipment comprises the following components: a decomposing pot, a washing tower, acondenser, an absorption kettle and a separator, which are communicated in order. Substances generated in the steps can be used as raw materials, cost is saved, and at the same time post-treatment process is reduced, production efficiency is improved, and large scale application of factory is facilitated. Absorption function of concentrated sulfuric acid is used, fluosilicic acid is decomposed into hydrogen fluoride and silicon tetrafluoride gas, so that effective utilization of fluosilicic acid is obtained. Dilute sulfuric acid is concentrated into concentrated sulfuric acid again, dischargeof dilute sulfuric acid is reduced, sulfuric acid becomes an intermediate, and fluosilicic acid is decomposed into hydrogen fluoride and silica.