The invention discloses a regulating process for diversification of products produced by a sulfuric acid plant. The regulating process comprises the following steps: converting liquid-state sulfur to prepare a furnace gas containing sulfur trioxide, passing the furnace gas through a nicotinic acid absorption tower to prepare a 98% sulfuric acid product; adding the 98% sulfuric acid product into a nicotinic acid circulating slot to absorb a sulfur trioxide gas to obtain 106.5-108.5% nicotinic acid; entering 105-108% nicotinic acid to a nicotinic acid evaporator to prepare the sulfur trioxide gas; condensing the sulfur trioxide gas and entering the condensed sulfur trioxide gas to a nicotinic acid mixer to obtain liquid sulfur trioxide; circulating and mixing the liquid sulfur trioxide with 105% nicotinic acid to prepare 65% fuming sulphuric acid; and carrying out liquid-phase synthesis on the sulfur trioxide gas with 95% hydrogen chloride gas to prepare a finished product chlorosulfonic acid with chlorosulfonic acid content of 98%. The regulating process can be used for overcoming the problem that the variety of products produced by the sulfuric acid plant is single, so that the profitability of the plant is effectively improved.