In　order　to　analyze　multi-transverse　modes　of　a　complex　index　waveguide,　a　numerical　method　named　RPS　is　proposed.　It　integrates　real　index　numerical　method,　perturbation　method　and　shooting　method　rationally.　The　method　is　simple,　fast　and　precise,　and　it　avoids　searching　the　solution　in　the　whole　complex　plane.　Numerical　example　shows　that　all　mode　solution　can　be　obtained　precisely　for　either　TE　mode　or　TM　mode　of　a　complex　index　waveguide.