Abstract: Objective：To explore the application value of 64-row CT with low-tube voltage and low-dose contrast agent combined with normal saline CT pulmonary angiography（CTPA） in pulmonary embolism (PE). Methods： 76 cases suspected of PE were divided into control group and observative group randomly with 38 cases in each group and accepted CTPA all. In control group，the contrast agent was 60 mL and the tube voltage was 120 kVp， while in observative group， the contrast agent was 40 mL and the tube voltage was 80 kVp and combined with 20 mL of normal saline. The rest scanning parameters are the same.The sensitivity， specificity， positive predictive value， negative predictive value， accuracy of diagnosis and subjective quality， objective quality and radiation dosage of 2 groups were compared respectively. Results： There were no significant differences in the sensitivity， specificity， positive predictive value， negative predictive value and accuracy of diagnosis between 2 groups (P>0.05). The comparison of subjective image quality showed the superior rate of observative group was higher than that control group (P<0.05)， and the qualified rate was without difference between 2 groups (P>0.05). The objective image quality comparison showed the image noise of observative group was higher than that of control group (P<0.05)， and the rest items were superior to control group (P<0.05). The radiation dose of observative group was significantly lower than that of control group (P<0.05). Conclusion： CTPA of 64-row CT with low-tube voltage and low-dose contrast agent combined with normal saline show important value in the diagnosis of PE， satisfactory image quality and higher diagnostic accuracy can be obtained while the radiation dose and the dosage of contrast agent can be reduced.