The invention discloses a novel viscoelastic particle oil displacement agent and a preparation method thereof, characterized in that the viscoelastic particle oil displacement agent is prepared by the steps of: dissolving 100 parts of acrylamide in 150-180 parts of deionized water to prepare aqueous solution, dissolving 0.35-0.5 parts of dimethylaminoethyl methacrylate in 20-40 parts of water to prepare solution, dissolving 0.03-0.05 parts of sodium bisulfite in 30-50 parts of water to prepare aqueous solution, sequentially adding the aqueous solutions and the solution into a reaction kettle which is provided with a stirrer, a thermograph and a reflux condenser, feeding nitrogen into the reaction kettle at 25 to 30 DEG C to remove oxygen for 15 minutes, then adding 0.03-0.05 parts of potassium persulfate aqueous solution dissolved in 30-50 parts of water, stirring at low speed under the protection of nitrogen, continuing preserving heat for 2 to 4 hours after system is gelled, and drying, crushing and screening slices of the product.