Background The rising incidence of ectopic pregnancy (EP) in China underscores the critical need for early and accurate diagnosis to achieve optimal patient outcomes. Colour Doppler ultrasound, β-hCG, and progesterone testing are essential tools in the detection of EP, with transvaginal ultrasound offering precise visualization of EP lesions. Lower levels of β-hCG and progesterone in EP cases compared to normal pregnancies serve as key diagnostic markers. Awareness of atypical symptoms is crucial to prevent missed or misdiagnosed cases, underscoring the importance of timely intervention to mitigate severe complications. Objective To investigate the differences in colour Doppler ultrasound findings, serum β-hCG levels, and progesterone levels between normal and ectopic pregnancies, in order to provide insights into the clinical diagnosis and treatment of EP. Methods Sixty patients who showed no gestational sac in the uterus during early pregnancy and were either highly suspected or pathologically confirmed to have EP were selected for this study. As controls, fifty women with normal pregnancies during the same period were also included. Colour Doppler ultrasound findings (endometrial thickness, pelvic effusion, uterine effusion, and adnexal mass), serum β-hCG levels, and progesterone levels were recorded and compared between the two groups. Results Colour Doppler ultrasound showed that the EP group had significantly greater incidences of pelvic effusion, uterine effusion, and an adnexal mass than did the control group. Moreover, the EP patients had significantly thinner endometria (8.3 ± 3.37 mm vs. 16.12 ± 3.09 mm; P < 0.05), lower serum β-hCG levels (846.18-1444.09 vs. 2429.24–3020.56; P < 0.05), and lower progesterone levels (9.1 ± 7.19 vs. 17.66 ± 5.63; P < 0.05) than did the controls. Receiver operating characteristic (ROC) analysis revealed that endometrial thickness, serum β-hCG concentration, and progesterone concentration had considerably high area under the curve (AUC), sensitivity, and specificity for the diagnosis of EP. Conclusion Colour Doppler ultrasound, serum β-hCG concentration, and progesterone concentration have high diagnostic value for EP.