The invention discloses an alkylated waste acid cracking technology adopting sulphur as fuel and especially a production technology of sulfuric acid by alkylated waste acid cracking in high-temperature environment generated by sulphur combustion. The technology comprises the following steps: cracking the waste sulfuric acid in high-temperature environment, recovering the heat from an exhaust-heat boiler, performing closed acid scrubbing and purifying, transforming for two times, absorbing for two times, absorbing the tail gas and so on, so that qualified sulfuric acid product is produced. Compared with commonly used gaseous fuels, such as the natural gas, the liquefied gas and the like, the fuel sulphur can be transformed into the product in the alkylated cracking technology, so that the device operation cost is greatly reduced; dilute acid efflux caused by H2O generated by gaseous fuel combustion is avoided, so that new waste discharge is thereby avoided; moreover, the alkylated waste acid cracking technology also reduces CO2 discharge generated by gaseous fuel combustion.