The invention discloses a method for preparing a carbon material with uniform pore sizes by a block polymer as a template. The method comprises 1) mixing an aqueous block polymer solution and an aqueous graphene oxide dispersion to obtain a polymer-mixed graphene oxide dispersion, 2) hydrothermally treating the dispersion for a reaction to obtain template-doped reduced graphene oxide aerogel, 3) dehydrating and drying the reduced graphene oxide aerogel under vacuum conditions to obtain graphene composite gel, 4) freeze-drying the reduced graphene oxide aerogel to obtain loose porous graphene aerogel, 5) tabletting the graphene aerogel to obtain graphene sheets and 6) carrying out heat treatment on the graphene composite gel and the graphene sheets to obtain a carbon material. The method has good controllability of the pore sizes. The carbon material can be processed into an all-solid-state electrode. The cylindrical carbon can be used as an adsorbent material.