Fretting maps of Zr alloy tube under grid-to-rod configuration in high temperature pressurised water were established. Running condition fretting map shows three fretting regimes, namely, partial slip regime, mixed fretting regime and gross slip regime. According to material response fretting map, the wear mechanism under partial slip regime is adhesive wear with the character of delamination of local regions, both adhesive wear and cracking are found for mixed fretting regime, while abrasive wear and severe delamination for gross slip regime. Compared with the results at room temperature, the mixed fretting regime range increases obviously at high temperature, while friction coefficient at high temperature is lower. In addition, fretting wear behaviour of Zr alloy tube under different fretting regimes is discussed. Display omitted •RCFM and MRFM of Zr alloy cladding tube in HTP water was established.•Compared with RT condition, the range of MFR increases obviously in HTP water.•The main wear mechanism under PSR and MFR is adhesive wear.•The main wear mechanisms under GSR are abrasive wear and delamination.