A porous crosslinked starch polymer (CSTO) using bitolylene diisocyanate as crosslinker was prepared by a facile method and used to selectively recover acetophenone (AP) from petrochemical effluent mainly containing AP and 1-phenylethanol (PE). The theoretical calculation results indicated that AP exhibited the superior affinity toward the adsorption sites of CSTO through noncovalent interactions. The adsorption measurements showed that, due to the large surface area and high affinity of phenyl rings, CSTO displayed an extremely rapid adsorption rate, a desirable adsorption capacity and selectivity to AP. The adsorption kinetics and isotherms in single solute system agreed well with the pseudo-second-order kinetic model and Freundlich isotherm model, and the adsorption was exothermic and spontaneous. Furthermore, CSTO showed excellent reusability for selective adsorption of AP from equimolar mixture of AP/PE, prompting us to further examine its applicability. In the practical application, CSTO also revealed a fast, preferential and reusable adsorption of AP from actual petrochemical effluent.