OBJECTIVE To investigate the eff ects of different habitat processing methods on the quality of Cyperus rotundus ， such as sun-drying after steaming ，sun-drying after boiling and direct sun-drying ，and to investigate the optimal habitat processing method of C. rotundus from the perspective of chemical component. METHODS The fingerprint of C. rotundus was established by high performance liquid chromatography （HPLC）combined with the Similarity Evaluation System for Chromatographic Fingerprint of TCM （2012 edition）. The similarity evaluation was conducted to determine the common peak. Cluster analysis （CA）combined with principal component analysis （PCA）and partial least squares-discriminant analysis （PLS-DA）was used to differentiate and compare C. rotundus treated by different habitat processing methods. And the contents of cyperrenone ，α-cyperone，luteolin and ferulic acid in C. rotundus were determined by HPLC. RESULTS There were 22 common peaks in the HPLC fingerprints of C. rotundus reated by different habitat processing methods ；their similarities were higher than 0.9；common peak 16 and common peak 20 were cyperrenone and α-cyperone. CA results showed that C. rotundus boiled for 4，8 and 12 min were clustered into one category，the rest of the samples clustered into one category. PCA results showed that comprehensive score of C. rotundus steamed for 10 and 15 min and boiled for 2 min were the highest. The steaming treatment had small effect on comprehensive score of samples，while the boiling treatment had a great effect on the quality of the samples ；the overall score of samples decreased sharply after boiling for 2 min. Results of PLS-DA showed that variable importance projection （VIP）of peak 20（α-cyperone），peak 16 （cyperrenone），peak 22，peak 17 and peak 22 in HPLC fingerprints were all higher than 1. The results of content determination showed that there was significant difference in the contents of α-cyperone，cyperrenone and luteolin in samples treated by different habitat processing methods.With the increase of steaming and boiling time ，the contents of α-cyperone，cyperrenone and luteolin showed a significant downward trend ，and boiling had a great impact on them. CONCLUSIONS Too long boiling treatment greatly；2019 destroys the chemical composition of C. rotundus ， andsteaming for 10，15 min or boiling for 2 min is the optimal processing method.