To develop EP1 receptor antagonists with higher activities, the key factors that affect the activities of EP1 antagonists were explored in this study. 103 EP1 antagonists were selected as data sets, and each molecule was calculated based on 254 parameters. Two regression methods of multiple linear regression (MLR) and principal component analysis (PCA) were used. The results show that the quantitative structure-activity relationship models using both the MLR and PCA exhibit good predictive ability. The statistical results by MLR show training set R2=077, SEE=083, test set R2=074, SEP=033, and those by PCA show training set R2=072, SEE=045, test set R2=071, SEP=038.