The invention provides a deep desulfurization apparatus for gasoline. The apparatus comprises a prehydrogenated gasoline cutting tower, a light gasoline etherification reactor, a catalytic reaction rectifying tower, and a heavy gasoline hydrodesulfurization reactor. The invention also relates to a deep desulphurization method for gasoline. The method comprises the following steps: (1) full range gasoline and hydrogen are mixed, firstly the materials enter the prehydrogenated gasoline cutting tower, diolefin and thiol are removed, cutting of light and heavy components is completed, and tower top light gasoline and tower bottom heavy gasoline are obtained; (2) the tower top light gasoline enters the light gasoline etherification reactor, and an etherification reaction is carried out between the light gasoline and methanol; (3) the tower bottom heavy gasoline enters the catalytic reaction rectifying tower, the catalytic reaction rectifying tower is filled with a gasoline alkylation sulfur transfer catalyst, an alkylation reaction is carried out between thiophene sulfide in gasoline and light olefin under the effect of the catalyst, and tower top middle gasoline after desulphurization and tower bottom heavy gasoline fraction are obtained; (4) the content of olefin in the tower bottom heavy gasoline fraction is reduced to 25%, the fraction enters the heavy gasoline hydrodesulfurization reactor, and tower bottom heavy gasoline after desulphurization is obtained.