The invention discloses a double-temperature multiple RT-PCR kit for simultaneously detecting two orchid viruses and a preparation method thereof, relates to a plant virus detecting kit, and provides a double-temperature multiple RT-PCR kit capable of simultaneously detecting two orchid viruses in one detection process and an application method thereof. The kit comprises a reagent A, a reagent B, a reagent C, a reagent D and a reagent E, wherein the reagent A is an RT reaction liquid which contains an M-MuLV reverse transcriptase buffer solution, random primers and dNTP; the reagent B is an M-MuLV reverse transcriptase; the reagent C is a PCR reaction liquid which contains a PCR buffer solution, MgCl2, dNTP and detection primers; the reagent D is a Taq polymerase; and the reagent E is a reference substance. Both positive control and negative control are established for each detection, and the application method comprises the following steps: carrying out reverse transcription; carrying out amplification detection, and determining the sizes of amplified bands according to the conventional agarose gel electrophoresis by taking 5 mu L of reaction products. The invention is especially applicable to the use by orchid enterprises, port quarantine authorities and related scientific research institutions.