The invention discloses a hollow platinum-copper-cobalt ternary alloy nanoparticle mimic enzyme and a preparation and application thereof. In the mimic enzyme, nano-particles are of a hollow structure, the Pt/Cu/Co molar ratio in alloy composition is 1.33:1:1, and the average particle size is 32.2+/-5.1 nm. The preparation method includes the steps that aqueous solutions of potassium chloroplatinate, copper chloride and nickel chloride are mixed, then polyvinylpyrrolidone, glycine and Co3O4 are added, and stirring and ultrasonic treatment are carried out to make the powder fully dispersed; thetemperature is increased to 180-210 DEG C, a constant-temperature reaction is carried out for 6-10 hours, after the reaction is finished, centrifugal separation and washing are carried out to obtainthe alloy nanoparticles, and the alloy nanoparticles are dispersed into water to obtain a platinum-copper-cobalt alloy nanoparticle mimic enzyme solution. The obtained platinum-copper-cobalt alloy nanoparticle mimic enzyme has very high chemical stability under strong acid, strong base, high salinity and high temperature conditions, and has potential application value in the fields of immunoassay,biological detection, clinical diagnosis and the like as a novel mimic enzyme.