The invention provides a method for optimizing adsorption of activated carbon to sulphur compounds in fuel oil. The method comprises the following steps: acquiring an adsorption isotherm that the activated carbon adsorbs a single thiophene sulphur-containing compound from the fuel oil through experiments; simulating a dynamic adsorption desulfurization process of the activated carbon to the thiophene sulphur-containing compound by utilizing COMSOL software until a simulated result is matched with an experimental result to obtain an adsorption equilibrium constant and a dynamic adsorption desulfurization curve of the activated carbon to the thiophene sulphur-containing compound; then, acquiring adsorption equilibrium constants of different thiophene sulphur-containing compounds and competition components; finally, simulating a dynamic adsorption desulfurization curve of the activated carbon to the fuel oil which contains mixed sulphur compounds and the competition components by utilizing the obtained adsorption equilibrium constant; analyzing the influence on a desulfurization effect of the activated carbon caused by different conditions by changing the conditions of simulation fuel oil to obtain adsorption desulfurization curves of the activated carbon under different conditions, and simulating and contrasting by utilizing the COMSOL software to optimize the desulfurization effect of the activated carbon.