Objective To explore the difference of the clinical manifestations between the elderly and non-elderly patients with non-massive pulmonary thromboembolism (PTE) and the significance of D-dimer in the diagnosis of PTE and its dynamic change after anticoagulant therapy.Methods The clinical manifestations of 83 cases with PTE were retrospectively analysed and divided into two groups:39 elderly and 44 non-elderly.The dynamic changing of D-dimer content was determined by immunoturbidimetry(ITM) method before and 3 d after anticoagulant therapy in the two groups.Results There were no significant statistical differences in the incidence of the main symptoms:dyspnea,cough,emptysis,syncope,palpitations between the elderly and the non-elderly (x2 =2.74,0.06,0.10,0.49,0.01,P＞0.05) except for the incidence of chest pain [14 cases (35.9 ％) vs.30 cases (68.2 ％),x2 =4.95,P ＜ 0.05].No differences were found in the the main signs:shortness of breath,tachycardia,accentuation or split of second pulmonary valve sound,cyanosis,and engorgement of neck veins between the two groups (x2 =2.60,0.03,0.61,0.06,0.33,0.11,P＞0.05).D-dimer content was lower in the elderly than in the non-elderly [(1.89±1.21) mg/L vs.(4.93±3.88) mg/L,Z=-2.55,P=0.01] before anticoagulant therapy.But there was no difference in D -dimer content between the two groups 3 d after anticoagulant therapy [( 1.28 ±1.11) mg/L vs.(2.09±2.22) mg/L,Z=-7.07,P=0.50].The decreasing level of D-dimer was less prominent in the elderly than in the non-elderly [(0.61±1.01) mg/Lvs.(2.84±2.95) mg/L,Z=-3.54,P=0.001].Conclusions The main clinical manifestations are similar between the elderly and non-elderly with non-massive PTE,but the incidence of chest pain is less in the elderly than in the non-elderly.The content of D-dimer is lower in the elderly than non-elderly after PTE and its decrements are less prominent in the elderly than the non-elderly after anticoagulant therapy.