Organicmechanochromic materials(also known as piezo-chromic materials),whose color or emission changes under mechanical force,have attracted great interest owing to their potential applications in pressure sensors,rewritable materials,optical storage,and security ink.Organic mechanochromic materials with aggregation-induced emission(AIE)features have better deve-lopment prospects and research value owing to their excellent opti-cal properties.To date,mechanochromism has mostly been realized by means of mechanical grinding.Nevertheless,the magnitude of the grinding force is usually uncontrollable and its direction is aniso-tropic,making it awkward to study the mechanism of mecha-nochromic materials.On the contrary,hydrostatic pressure,whose magnitude and direction are controllable,is a more valid and go-vernable method to investigate the mechanism of mechanochromic materials,which can help us to construct a meaningful structure-property relationship and understand the latent origin of the me-chanochromism.Furthermore,it is conducive to developing other mechanochromic material systems with desired chemical and phy-sical properties.In this review,we focus on the recent progress in the mechanism of organic mechanochromic materials with AIE fea-tures under hydrostatic pressure.Four types of mechanisms are in-cluded:intermolecular interaction change,intramolecular confor-mation change,transformation from locally excited state to intramo-lecular charge-transfer state,and intra-and inter-molecular effects induced by hydrostatic pressure,respectively.