Objective: This study aims to evaluate the predictive value of nailfold capillaroscopy (NVC) in the diagnosis of patients with connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH). Methods: A retrospective analysis was conducted on One hundred and forty-seven patients with connective tissue disease (CTD) who were hospitalised in the Department of Rheumatology and Immunology of the First Affiliated Hospital with Nanjing Medical University and underwent nailfold video capillaroscopy from September 2022 to June 2024. According to whether they were combined with pulmonary arterial hypertension (PAH) or not, CTD patients were divided into two groups: CTD-PAH and CTD-nonPAH. Risk factors for PAH in CTD patients were screened by multifactorial logistic regression analysis. A Nomogram prediction model was constructed based on this multifactorial logistic regression analysis and the model performance was evaluated using the receiver operating characteristic (ROC) curve. Results: Among the CTD patients, 52 (35.4%) were included in the CTD-PAH group. The capillary length was longer in the CTD-PAH group than in the CTD-nonPAH group [202.0 (160.0, 272.0) vs. 262.0 (207.0, 308.0), P<0.05], and the pericapillary score was higher than that in the CTD-nonPAH group [1.90 ( 0.40, 2.80) vs. 2.40 (0.80, 3.92),P<0.05]. Logistic regression analysis showed that both long capillary length and high pericapillary score increased the risk of PAH occurrence [OR=1.300 (95% CI: 1.100-1.500), OR=1.268 (95% CI: 1.025-1.568)]. The area under the ROC curve of the Nomogram prediction model amounted to 0.6913 (95% CI:0.6046~0.7781, P<0.05). Conclusion: The findings suggest that nailfold capillary characteristics, including capillary length and pericapillary score, may serve as independent predictors of PAH in patients with connective tissue diseases. These results provide a new basis for early screening and individualized therapeutic strategies in CTD-PAH patients.