The invention discloses an infectous clone construction method for a recombined single-chain negative righteousness plant virus, a plasmid and a virus. A mixture for introducing a plasmid vector into a plant cell comprises a transcription vector (i), at least one expression vector (ii) and one or more separated nucleic acid molecules (iii) in a polynucleotide sequence of a silence suppression sub protein capable of suppressing gene silence in a plant body, wherein the transcription vector comprises a separated nucleic acid molecule which contains a polynucleotide sequence for encoding a single-chain negative righteousness plant virus antigenome; each expression vector comprises a trans-acting protein necessary for encoding capsid packaging, transcription and copying of the single-chain negative righteousness plant virus. After a plasmid vector combination is introduced into the plant cell, a large quantity of recombined plant negative-chain RNA viruses can be produced; infectous clone can efficiently infect at least more than one plant, and no expensive equipment is needed; the infectous clone construction method is easy to operate and high in repetitiveness; the infectous clone can be effectively used for trans-genetics research on the plant negative-chain RNA viruses.