Disclosed is a building curtain wall viscoelastic damping connection mechanism which is connected between a curtain wall and a structural main upright post via a supporting base. The building curtain wall viscoelastic damping connection mechanism is characterized in that the lower side of the supporting base is fixedly connected with a supporting base adaptor, the supporting base adaptor is a rectangular frame body, two sides of the frame body are respectively provided with an regulating hole, a pair of clamping block supports are symmetrically supported in the two regulating holes, each clamping block support is connected with a clamping block, two clamping blocks are in symmetrically embracing connection to two sides of the structural main upright post, and viscous rubber pads are connected between each clamping block and the structural main upright post. The utility model guarantees regulating relative positions of the building curtain wall and a superstructure on three-dimensional direction, prevents affecting the curtain wall when the superstructure shocks and shifts, keeps stability of the curtain wall in full service life, and further increases shock absorption and vibration resistance of a building curtain wall system.