The invention discloses a microcircuit internal atmosphere detection test clamp and relates to the field of reliability and environment tests of electronic products. The clamp comprises a primary clamp body, a secondary clamp body and a cover body, wherein an inwards concave press cavity is formed in the central position of one end of the primary clamp body and used for accommodating the secondary clamp body, a through connecting channel is formed in the press cavity and used for accommodating a to-be-tested device, a yield part is arranged on the peripheral edge, located on the same side of an opening part of the press cavity, of the primary clamp body and used for mounting a seal ring, and the cover body covers the opening of the press cavity and the seal ring. The clamp provides a new thought for accommodating of the to-be-tested device, that is, the connecting channel with the diameter slightly larger than that of the to-be-tested device is designed, the to-be-tested device is put in the connecting channel, the sealing property of the clamp and protection of the to-be-tested device are greatly improved, besides, the matched secondary clamp body is designed, can fix the to-be-tested device and can greatly reduce vacant space in the clamp, and influence of the atmosphere of the clamp on the detection result is further reduced.