The invention relates to a method for preparing porous silicon carbide ceramic through low temperature sintering. The method comprises the steps of (1) mixing SiC powder, SiC sintering aid, absolute ethyl alcohol and polyvinyl alcohol and then grinding, drying to obtain a SiC porous ceramic sintering raw material; (2) preparing a multi-channel tubular test piece through an extruding forming machine, putting into a 200 DEG C muffle furnace, preburning for 2 hours, and cooling along with the muffle furnace, so as to prepare a multi-channel tubular SiC porous ceramic blank; (3) putting the multi-channel tubular SiC porous ceramic blank prepared in step (2) into a tube furnace, heating up to 200DEG C at the speed of 6 DEG C per minute in a nitrogen atmosphere, then heating up to 1200-1300DEG C at the speed of 9 DEG C per minute, preserving heat for 2 hours, and cooling down to room temperature along with the furnace, so as to prepare the SiC porous ceramic. The method has the beneficial effects of having highly connected voidage and high breaking strength, improving the usability, being capable of sintering at lower temperature, and saving energy.