The invention discloses a restaurant wastewater deoiling treatment system which comprises a buffer pool, a coarse grid, a microbubble air floatation oil adsorption device, an oil catalyzing, heightening and desorbing reactor, a pH value adjusting tank, a primary sedimentation tank, an organic rhodium catalysis reaction tank, a biological denitrification tank, a second sedimentation tank and a water purification tank. According to the system, the catalytic action of pion-allyl nickel compound to oil molecules is creatively utilized; when oil in the wastewater is adsorbed by modified keiselguhrand is under a temperature of 200 to 250 DEG C, C-H bonds in the oil molecules can be temporarily broken under catalysis of the pion-allyl nickel compound and quickly combined into C-C bonds or C-H bonds, the C-H bonds can be broken again, and the C-C bonds cannot be broken again as the catalytic action of the pion-allyl nickel compound is limited; thus, the oil molecules with shorter carbon chains can be gradually synthesized into heavy oil molecules with longer carbon chains.