The invention relates to a method for preparing carbon nanotubes and carbon nanofiber with phenolic resin as the carbon source. The method includes the following steps: preparing 10wt % aqueous solution from 1-3wt% based on base material weight into the nickel nitrate, and mixing with the base material which is at least one out of alumina powder and crystalline flake graphite and baked to remove the moisture; adding 3-15wt% phenolic resin to the base material mixed with nickel nitrate catalyst, mixing, and pressing under a pressure of 100-200MPa to obtain the lump material; drying into a drying oven until moisture content reaches 1.0-2.0wt%, carbon burial heating in a resistance furnace up to 1,200-1,450 DEG C and holding for 4-5 hours, and cooling to 0-45 DEG C to grow carbon nanotubes orcarbon nanofiber on the alumina and graphite substrate. The method has the advantages that the preparation method and process are simple and the processing parameters are easily controlled; carbon source for preparing carbon nanotubes and carbon nanofiber adopts the phenolic resin as the bonding agent for refractory material with low cost and easy accessibility; and the obtained carbon nanotubesand carbon nanofiber have large quantity, diameter of 50-400m, length of tens of micrometers, and clear hollow structure as displayed in scanning electron microscope photos, and grow on the substratematerial with a bundle shape with good growth condition.