Objective To detect in vivo and in vitro activities of Leptospira interrogans (L.interrogans) collagenase in order to identify the role of collagenase (LA0872) of Leptospira interrogans serovar Lai strain Lai in the pathogenesis of hemorrhage caused by pathogenic leptospira. Methods Recombinant la0872 was cloned and expressed in E.coli, and enzyme activity was detected by gelatin zymography. The differences in collagenase gene, transcription and enzyme activity among three leptospira strains with different virulence (L.interrogans serovar Lai strain Lai, avirulent variant strain of L.interrogans serovar Lai strain Lai and L.biflexa serovar montevalerio strain Monte Valerio) were compared. Furthermore, the changes of serum collagenase activities of guinea pigs and gerbils infected by L. interrogans serovar Lai strain Lai were detected. Results Recombinant la0872 was successfully identified with collagenase activity. There was no significant difference in collagenase gene, transcription and enzyme activity among three leptospira strains with different virulence. There was no significant difference between the serum activities of collagenase of guinea pigs and gerbils with infection by L.interrogans serovar Lai strain Lai and those without infection (P>0.05). Conclusion It is the first time to express L.interrogans collagenase and identify its activity, however, its role in leptospirosis hemorrhage still needs to be further studied.