Abstract: ObjectiveTo analyze the clinical significance of Ddimer (DD) and fibrinogen (FDP) in relapsing polychondritis（RPC）and respiratory tract involvement. MethodsA retrospective analysis of  DD and FDP was performed in 52 cases of confirmed RPC patients hospitalized in the First Affiliated Hospital of Zhengzhou University in January 2010  December 2015. And the difference of DD and FDP levels of respiratory tract involvement and noninvolvement patients were compared. Results29 cases (55.8%) in 52 RPC patients were with laryngeal and tracheal， bronchial cartilage inflammation of respiratory tract.37 cases (71.2%) with higher level  DD，FDP or both. Serum DD and blood sedimentation were positively correlated (r=0.635，P=0.000). And the CRP positive correlation (r=0.421，P=0.002).Serum FDP positively related to the blood sedimentation (r=0.725，P=0.000); And CRP (r=0.689，P=0.000).The DD differences between patients with respiratory tract involvement and non  involvement appeared  statistically significant (P<0.001)， the difference of FDP had no statistical significance (P=0.146).ConclusionRespiratory tract involvement is not uncommon in RPC， and it is the most important factor influencing the prognosis of RPC.DD and FDP detection are of great significance for determining RPC disease activity， DD and elevated FDP and respiratory tract involvement have important relation， with ESR and CRP，these inflammation markers can be the indexes of disease activity or severity.

Key words: polychondritis, relapsing； Ddimer； fibrinogen