In　consideration　of　the　disadvantages　such　as　boundary　distortion　and　poor　adaptability　in　the　method　for　microstructure　surface　error　separation,　the　bidimensional　empirical　mode　decomposition　(BEMD)　with　adaptive　time-frequency　resolution　capacity　was　put　forward　and　applied　to　three-dimensional　engineering　surface　error　separation;　at　the　same　time,　Riesz　transform　was　utilized　to　construct　monogenic　signal,　calculated　overall　frequency　characteristics　of　the　signal　and　improved　the　termination　criterion　for　bidimensional　empirical　mode　decomposition,　thus　keeping　it　in　strict　accordance　with　the　error　specified　in　ISO4287　for　each　frequency　band　of　the　3D　surface　with　cutoff　wavelength　and　long　separation.　The　simulation　results　show　that　compared　with　Gaussian　filter　in　ISO　and　commonly-used　wavelet　filter,　this　new　method　can　achieve　a　far　better　separation　effect　than　traditional　methods　in　error　separation　for　3D　engineering　rough　surface,　and　the　3D　evaluation　parameter　errors　corresponding　to　the　error　in　each　frequency　band　are　all　lower　than　5%.　Finally,　an　instance　analysis　was　conducted　in　the　optical　filming　elements,　and　the　results　show　that　the　method　can　well　separate　the　spatial　information　of　each　surface　error,　and　the　reference　surface　for　parameter　evaluation　is　free　from　problems　such　boundary　distortion　compared　with　traditional　methods.　Hence,　the　application　of　the　method　in　actual　engineering　surface　error　evaluation　is　of　great　feasibility.　©　2017,　Science　Press.　All　right　reserved.