The prismatic theory was introduced by Bhatt and Scholze in 2018. It is a powerful tool to study p-adic Hodge theory. In this talk, I will study Hodge–Tate crystals on (OK)∆. I will give an explicit description of Hodge–Tate crystals and show how they are related to Cp-representations of GK. If time permits, I will introduce the relative case. All works are joint with Yu Min.