Modification　is　one　of　the　most　important　and　effective　methods　to　improve　the　photoelectrocatalytic　(PEC)　performance　of　ZnO.　In　this　paper,　the　RuxZn1−xO/Ti　electrodes　were　prepared　by　thermal　decomposition　method　and　the　effect　of　Ru　content　on　those　electrodes’　electronic　structure　was　analyzed　through　the　first-principles　calculation.　Various　tests　were　also　performed　to　observe　the　microstructures　and　PEC　performance.　The　results　showed　that　as　the　Ru4+　transferred　into　ZnO　lattice　and　replaced　a　number　of　Zn2+,　the　conduction　band　of　ZnO　moved　downward　and　the　valence　band　went　upward.　The　number　of　photogenerated　electron-hole　pairs　increased　as　the　impurity　levels　appeared　in　the　band　gap.　In　addition,　ZnO　nanorods　exhibited　a　smaller　grain　size　and　a　rougher　surface　under　the　effect　of　Ru.　Meanwhile,　the　RuO2　nanoparticles　on　the　surface　of　ZnO　nanorods　acted　as　the　electron-transfer　channel,　helping　electrons　transfer　to　the　counter　electrode　and　delaying　the　recombination　of　the　electron-hole　pairs.　Specifically,　the　RuxZn1−xO/Ti　electrodes　with　9.375　mol%　Ru　exhibited　the　best　PEC　performance　with　a　rhodamine　B　(RhB)　removal　rate　of　97%,　much　higher　than　the　combination　of　electrocatalysis　(EC,　12%)　and　photocatalysis　(PC,　50%),　confirming　the　synergy　of　photoelectrocatalysis.[Figure　not　available:　see　fulltext.]　©　2021,　The　Author(s).