Phenol hydroxylase (PH) is known to degrade trichloroethene (TCE) aerobically. PH gene consists of 6 structural genes, phyZABCDE. Here we selected two different types of PH genes and developed hybrid PH by exchanging structural genes. Firstly two same structural genes were exchanged, and changes on TCE degradability were examined. Resultantly phyZ and phyE were found to have some roles to improve TCE degradation. As a next step, multiple gene exchanges were carried out to examine more detail functions of structural genes. Remarkable improvements of TCE degradability were found in some hybrid PH genes, showing effectiveness of hybrid PH development.