The study verified the diagnostic accuracy of the HUAWEI WATCH D for measuring hypotension induced by spinal anesthesia in 118 healthy parturients during elective caesarean section. Blood pressure was measured three times preoperatively in both arms using a HW on the left wrist and an Omron monitor on the right upper limb, with mean baseline values recorded. After spinal anesthesia, it was measured simultaneously on both sides at 1-minute intervals 10 times, resulting in 1180 pairs of systolic blood pressure. Hypotension was defined as SBP < 80% of baseline according to NIBP as the gold standard. The HW watch had a Youden index of 0.62 with a hypotension threshold of 104 mmHg, a sensitivity of 79.2%, a specificity of 82.0%, a false positive rate of 18.0% and a false negative rate of 30.8%, an accuracy of 81%. Chi-square test showed Pearson's χ² = 350.4, Kappa = 0.53, P < 0.001 and AUC ROC 0.87 (95% CI: 0.85–0.90), P < 0.001. HUAWEI WATCH D demonstrated moderate diagnostic accuracy for the detection of severe hypotension (SBP < 80% of baseline) during caesarean section.