The invention discloses a multiplex PCR (polymerase chain reaction) detection reagent of porcine circovirus type II, porcine parvovirus and porcine pseudorabies virus and special primers thereof. The invention provides the special primers for detecting the virus, and the special primers comprise a primer pair A, a primer pair B and a primer pair C, wherein the primer pair A comprises a primer 1 and a primer 2, the primer pair B comprises a primer 3 and a primer 4, the primer pair C comprises a primer 5 and a primer 6, and the nucleotide sequences of the primer 1, the primer 2, the primer 3, the primer 4, the primer 5 and the primer 6 are respectively as shown in the sequence 1, the sequence 2, the sequence 3, the sequence 4, the sequence 5 and the sequence 6 in a sequence table. Experiments prove that the multiplex PCR detection method of the porcine circovirus type II, the porcine parvovirus and the porcine pseudorabies virus provided by the invention is simple, convenient, fast, economical and efficient and has great application prospects in clinical diagnosis.