The invention provides a double-layer curtain wall connecting assembly and relates to the field of curtain wall connecting pieces. The double-layer curtain wall connecting assembly comprises outer-layer perforated aluminum plates, cast steel claw pieces, a cross beam, a telescopic connecting rod and a vertical column. The two cast steel claw pieces are mounted on the rotation surface of the crossbeam and distributed with the axis center of the cross beam as the symmetrical axis, and each cast steel claw piece is connected with the corresponding outer-layer perforated aluminum plate. The two outer-layer perforated aluminum plates are also distributed with the axis center of the cross beam as the symmetrical axis, the telescopic connecting rod is further connected to the cross beam, and thetelescopic connecting rod and the cross beam keep the perpendicular position relation. The telescopic connecting rod is further connected with the vertical column. According to the double-layer curtain wall connecting assembly, cross keels of the outer-layer perforated aluminum plates are canceled, aluminum profile with a small notch is adopted to be arranged in a full-length mode in the longitudinal direction, the material use quantity is decreased, the strength and deflection of a perforated plate are improved, and the manufacturing cost is saved by about 5%.