In　this　paper,　we　propose　an　interpolated　computationally　efficient　subspace-based　method　without　eigendecomposition　(ISUMWE)　for　the　direction-of-arrivals　(DOA)　estimation　of　narrowband　coherent　signals　in　arbitrary　linear　arrays.　ISUMWE　estimates　DOA　based　on　the　outputs　of　the　virtual　array　by　using　an　interpolation　transform　technique.　Therefore,　it　overcomes　the　common　restriction　of　uniform　linear　array　(ULA)　geometry　when　estimating　coherent　signals　and　becomes　suitable　for　more　general　array　geometry　than　ordinary　methods.　Meanwhile,　the　coherency　of　incident　signals　is　decorrelated　through　a　linear　operation　of　a　matrix　formed　from　the　cross-correlations　between　some　sensor　data　in　a　designed　virtual　array　which　can　be　computed　from　the　linear　transformation　of　sensor　data　in　the　real　array,　where　the　effect　of　additive　noise　is　eliminated.　Consequently,　the　DOA　can　be　estimated　without　performing　eigendecomposition,　and　the　noise　pre-whitening　which　is　required　in　traditional　interpolation　procedure　can　be　avoided.　As　a　result,　the　ISUMWE　extends　the　application　of　the　original　subspace-based　method　without　eigendecomposition　(SUMWE)　into　arbitrary　linear　array　with　high　accuracy　and　low　computational　complexity.　The　numerical　results　demonstrate　the　validity　of　the　proposed　method.　©　2019,IEEE