OurRef.:PUS 1 Compounds serving as histone deacetylase 6 (HDAC6) selective inhibitors, and applications thereof in the preparation of drugs for treating HDAC6-related diseases. Specifically disclosed are a compound as represented by formula (I) and a pharmaceutically acceptable salt thereof. T2 T3 T1 A R1 Z1 Z3 Z2 H OH O L1 n (I) R2