The yigP gene is located between ubiE and ubiB gene which concerned CoQ biosynthesis process of Escherichia coli. These three genes are transcribed as an operon. After inactivation of the gene yigP located at chromosome by the system of temperature-sensitive plasmid pMAK705, we found that the temperature-sensitive-plasmid in sub-recombinant couldn't be lost at high temperature cultivation. In other words, knockout yigP of chromosome could cause Escherichia coli (E.coli) inviability only when it had complete yigP in plasmid. Through anaplerotic experiment we found that both pLac-yigP and the DNA fragment yigP-P4P2 could transform into the yigP gene deficiency variant strain. It showed that gene yigP is essential for the growth of E. coil, and the functional region of yigP gene could shrink to yigP-P4P2 domain of 367 bp.