The invention discloses a titanium carbon/nickel composite powder electromagnetic wave absorbent. The absorbent is composed of Ti3C2 and Ni; the mass fraction of the Ti3C2 is 50%-90%; the mass fraction of the Ni of 50%-10%. The invention further discloses a preparation method. The method comprises the steps of performing ethanol washing, coarsening, sensitizing, activating, water washing and drying to the prepared Ti3C2 powder body to acquire the Ti3C2 powder, preparing nickel plating solution by using NiSO4.6H20, ammonium chloride and sodium citrate, reducing Ti3SiC2 powder by sodium hypophosphite solution, and finally, cleaning and drying. Nanometer Ni is plated on the surface of the Ti3C2 by a chemical plating method, so that the weight of the material is significantly reduced. At the same time, the Ti3C2/Ni composite powder electromagnetic wave absorbent prepared by the method is characterized in electromagnetic loss characteristic and low density.