The invention discloses a bovine-para-influenza virus 3 nano-PCR (polymerase chain reaction) detection kit and a preparation method thereof, relates to the field of bovine para-influenza virus detection, and solves the problems that an existing bovine-para-influenza virus 3 detection method is low in sensitivity, serological detection is high in false positive and foreign importing reagents are expensive. The kit comprises a MightyAmp enzyme, 2xBuffer Mix solution, gold nanoparticle sol, aseptic double-distilled water, a pair of specific primers P1 (5'-GCTCTTCTCTTTTTGTCCCATTCTT-3') and P2 (5'-AACCCCTTCCTCAATCCTGATATAC-3') and a bovine-para-influenza virus 3 positive control plasmid. The sequence of the bovine-para-influenza virus 3 positive control plasmid is as shown in SEQ ID NO: 2. The kit is high in sensitivity, simple, convenient, rapid, efficient and low in cost.