Objective: This study aimed to investigate the effects of a kidney-nourishing and blood-activating acupuncture protocol on natural killer (NK) cell activity and uterine artery hemodynamic parameters in recurrent miscarriage (RM) patients with kidney yang deficiency and blood stasis syndrome and to analyze their correlation, thereby providing new insights and a theoretical basis for clinical treatment. Methods: A total of 134 patients diagnosed with RM of kidney yang deficiency and blood stasis syndrome, who visited Beijing Hospital of Traditional Chinese medicine (TCM) between January 2023 and December 2023, were selected as research subjects. All patients received the kidney-nourishing and blood-activating acupuncture protocol three times per week for 12 consecutive weeks. Peripheral blood NK cell activity, uterine artery hemodynamic parameters [including resistance index (RI), pulsatility index (PI), and systolic/diastolic ratio (S/D)], and serum levels of tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) were measured before and after treatment. Pearson correlation analysis was used to analyze the relationships between NK cell activity and hemodynamic parameters and serum factors. TCM syndrome scores and clinical efficacy were also observed. Results: After 12 weeks of treatment, patients’ peripheral blood NK cell activity significantly decreased from 22.45 ± 5.67% to 15.32 ± 4.28% (P < 0.01). Uterine artery hemodynamic parameters showed marked improvement: RI decreased from 0.75 ± 0.07 to 0.66 ± 0.06, PI from 1.81 ± 0.34 to 1.61 ± 0.30, and S/D from 3.21 ± 0.49 to 2.81 ± 0.44, all showing statistical significance (P < 0.01). Serum TNF-α levels decreased from 38.56 ± 6.78 pg/mL to 28.93 ± 5.12 pg/mL, and IFN-γ levels decreased from 16.92 ± 3.45 pg/mL to 12.67 ± 2.89 pg/mL (P < 0.01). TCM syndrome scores decreased from 18.45 ± 3.67 to 7.65 ± 2.14 (P < 0.01). Correlation analysis revealed significant positive correlations between NK cell activity and uterine artery RI (r = 0.485, P < 0.001), PI (r = 0.432, P < 0.001), and S/D (r = 0.398, P < 0.001), as well as with serum levels of TNF-α (r = 0.462, P < 0.001) and IFN-γ (r = 0.415, P < 0.001). Among the 134 patients, 41 achieved complete recovery, 46 showed marked effectiveness, 31 showed improvement, and 16 showed no effect, with a total effective rate of 88.06%. During the 6-month follow-up, 85 patients achieved successful pregnancy, representing a pregnancy rate of 63.43%. Multivariate logistic regression analysis indicated that the degree of NK cell activity reduction [odds ratio (OR) = 2.186, 95% confidence interval (CI): 1.352–3.534] and improvement in uterine artery RI (OR = 1.812, 95% CI: 1.228–2.672) were independent predictors of successful pregnancy. Conclusion: The kidney-nourishing and blood-activating acupuncture protocol effectively reduces NK cell activity, improves uterine artery hemodynamics, and regulates immune-related factors in RM patients with kidney yang deficiency and blood stasis syndrome. Significant correlations exist between NK cell activity and uterine artery hemodynamic parameters and immune factors, providing evidence for the clinical application of this treatment approach.