Abstract: Many results have shown SPINDLY (SPY) is involved in gibberellic acid (GA) signaling as a negative regulator, the tetratricopeptide repeat domain and C-terminal region have important roles for its function. The SPY gene is expressed constitutively in plants, and most of the SPY protein presents in nucleus. The SPY protein has significant similarity to O-linked GlcNAc transferase (OGT) from animals, which suggests that it may also have OGT activity. In this review, we highlighted research progress GA mutants、function of SPY gene and SPY protein and the homologue in barley (HvSPY).