The method for simultaneously raising treatment capacity of delayed coking equipment and diesed oil yield, includes the following steps: heating the coking raw material to 480 deg.C-510 deg.C by means of first heating furnace, then heating coker gas oil and arbitrarily-selected straight-run gas oil and deasphalted oil to 510 deg.C-580 deg.C by means of second heating furnace; feeding the materials obtained by above-mentioned two heating furnaces into coke drum for coking, remaining the coke in coke drum and separating coking oil gas to obtain coker gas, coker dgasoline, coker diesel oil and coker gas oil, in which feeding coker gas oil into second heating furnace, can raise equipment treatment capacity by up to 50%.