Triplet-triplet annihilation(TTA) upconversion is a technique converting low energy photos into high energy photos by a multi photon mechanism.The TTA based upconversion has a broad application prospect in solar cells,photocatalytic,anti counterfeiting and bioimaging,etc.The traditional TTA based upconversion mainly occurs in anaerobic solution,which may significantly limit its applications.Recently,the development of TTA upconversion in solid state has attracted much attention.And the development over the past ten years of solid state TTA upconversion in polymer matrix from the state of polymer and the dispersion mode of TTA system is summarized in this review.