An　improved　time-domain　physical　optics　(TDPO)　method　is　proposed　to　simulate　multilayered　dielectric　structures,　in　which　the　characteristic　matrix　theory　of　multilayered　medium　is　implemented.　In　order　to　accurately　calculate　the　total　reflection　coefficient　on　the　surface　of　the　multilayered　medium,　a　series　of　two-dimensional　characteristic　matrices　are　established.　Based　on　the　characteristic　matrices,　the　total　reflection　coefficient　can　be　directly　derived,　instead　of　summing　up　the　multiple　reflected　and　refracted　waves,　which　is　insensitive　to　the　number　of　the　number　of　the　layers　and　the　polarization　of　the　incident　wave.　Numerical　examples　are　given　to　validate　effectiveness　of　the　proposed　TDPO　method.　It　states　that　this　method　has　much　higher　computational　efficiency,　without　the　loss　of　accuracy.　©　2019　Wiley　Periodicals,　Inc.