Objective To investigate the correlation between elevated Δ D-dimer and pulmonary embolism (PE).Methods 260 cases were included in the Second Affiliated Hospital of Xi'an Jiaotong University from June 2017 to July 2018 for pulmonary angiography (CTPA) to determine whether they were pulmonary embolism. Before the examination, 260 cases had been tested for D-dimer twice. According to the results of whether or not Δ D-dimer increased, they were divided into Δ D-dimer ＞0 group and Δ D-dimer ≤0 group. Logistic regression models were used to analyze the possibility of the occurrence of pulmonary embolism. Results In this study, 150 patients in the group of Δ D-dimer ＞ 0 and 110 patients in the group of Δ D-dimer ≤0 were collected; The median of Δ D-dimer was 2960 (〖CD*3/5〗15，6660) in pulmonary embolism group and 5 (〖CD*3/5〗1000，1327.5) in nonpulmonary embolism group (P＜0.001). 41.3% patients in the group of pulmonary embolism had Δ D-dimer＞0, 20.0% in the group of pulmonary embolism had Δ D-dimer ≤0, the difference was statistically significant (P＜0.001). Univariate logistic regression analysis showed that the possibility of delta D-dimer＞0 in pulmonary embolism is 2.755 times than the delta D-dimer＜0 (OR=2755, 95%CI: 1.559-4.867); Multivariate logistic regression analysis showed that the possibility of Δ D-dimer ＞0 in pulmonary embolism is 2.829 times than the Δ D-dimer≤0（OR=2.829，95%CI：1.533-5.221）.In non-tumor patients, the risk of pulmonary embolism was 3.038 times (OR=3.038 95% CI:1.569-5.884) when Δ D-dimer＞0; multivariate logistic regression showed that the risk of pulmonary embolism was 2.870 times (OR=2.870 95% CI: 1.414-5.825) when Δ D-dimer＞0.Conclusion There is a high correlation between the changes of D-dimer and pulmonary embolism. Paying attention to the changes of D-dimer promotes our attention to pulmonary embolism and improves the early detection rate of pulmonary embolism.It is more significant in non-tumor patients.