Building heat insulation roof

The utility model relates to the technical field of building structures, in particular to a building heat insulation roof which comprises a roof beam frame, symmetrical heat insulation plates are installed above the roof beam frame, a heat insulation mechanism is arranged above the heat insulation plates, the heat insulation mechanism comprises a hollow plate and a reflection tile face, the hollow plate is arranged on the top of the heat insulation plates, and the reflection tile face is arranged on the top of the heat insulation plates. The interior of the hollow plate is of a hollow structure, and the reflecting tile surface is mounted at the top of the hollow plate; the bottom end of the hollow plate is provided with a backflow box, the backflow box is communicated with the bottom end of the hollow plate, the top of the backflow box is provided with a heat dissipation mechanism, the heat dissipation mechanism comprises an air outlet frame and a fan, the top of the hollow plate is provided with a collection