Objective: To study how to protect epithelial attachment and biological width during subgingival tooth preparation in fixed restoration, and achieve precise impression. Methods: 262 teeth in 86 cases were restored with fixed bridges, gingival retraction cord was used to retract the gingiva and gingiva block was used to protect peripheral tissue during tooth preparation, gingival retraction paste was used to retract the gingiva after preparation. Results: The effect of gingival retraction and hemostasia, the clearness of impression around gingival margin and gingival sulcus were both improved. Conclusion: Reasonable application of gingival retraction technique can not only prevent damage to gingival tissue and hemostasia caused by tooth preparation but also make the gingival sulcus open quickly, and besides, gingival retraction is completely reversible.