［Abstract］Objective To explore the normal reference interval of plasma D-dimer test in elderly and young people. Methods 1208 healthy peoples in our hospital from January 2015 to December were selected and divided into three groups according to the different age，the group of age less or equal to than 39 years old（381 cases），the group of age from 41 to 59 years old（416 cases），the group of agemore or equal to than 60 years old（411cases）.The level of plasma D-dimer in each group was detected.Results There was no significant difference in the level of plasma D-dimer between the group of age less or equal to than 39 years old and the group of age from 41 to 59 years old（P＞0.05）.There was significant difference in the level of plasma D-dimer between the group of age from 41 to 59 years old and the group of agemore or equal to than 60 years old（P＜0.01）.The normal reference range of the level of plasma D-dimer in the age less or equal to than 59 years old was less than 528.28μg/L，the normal reference range of the level of plasma D-dimer in the agemore or equal to than 60 years old was less than 703.70μg/L.Conclusion Plasma D-dimer level is associated with age，with the increase of age，the level of plasma D-dimer is riseing.The normal reference range of plasma D-dimer level is different between the elderly and the young people.Different age groups should be used different instruments and the appropriate reagents，the laboratory should be established its own reference range.

［Key words］Age；Healthy population；D-dimer；Reference interval