The　purpose　of　this　paper　is　to　investigate　the　forecasting　control　of　adjacent　buildings　with　optimal　grey　model　(GM).　Firstly,　based　on　the　linear　quadratic　regulator　(LGR)　control,　a　novel　forecasting　control　scheme　for　adjacent　buildings　using　optimal　GM　is　proposed,　the　calculation　model　is　established,　and　the　motion　and　control　equations　are　derived.　Secondly,　a　numerical　investigation　of　a　complex　system　with　two　adjacent　buildings　is　conducted,　and　the　influence　of　time　delay　on　control　of　adjacent　buildings　is　analyzed.　Finally,　the　effect　of　forecasting　control　on　the　time　delay　of　adjacent　buildings　is　studied.　The　numerical　results　indicate　that　the　forecasting　control　method　based　on　optimal　GM　is　reliable　and　practical　in　vibration　control　of　buildings,　particularly　in　the　case　of　adjacent　buildings.