Abstract: This paper lists mitochondrial plasmid DNAs which have been found in higher plants and divides them into mitochondrial circular plasmid DNAs and mitochondrial linear plasmid DNAs. Mitochondrial circular plasmid DNAs are smaller . They usually contain direct and/or inverted repeats and smaller ORFs . Mitochondrial linear plasmid DNAs are larger, and they contain terminal inverted repeats ,proteins covalently bound at 5' terminus,and longer ORFs. Replication, transcription and origin of the two kinds of mitochondrial plasmid DNAs are introduced respectively. The homology among plasmids and the homology between plasmids and nuclear genome,mitochondrial genome ,chloroplast genome are also introduced. The relationship between plant mitochondrial plasmid DNAs and cytoplasmic male sterility (CMS) is discussed.