Objective:To evaluate left atrial volume and function in diabetes patients using real time three-dimension echocardiography. Methods：This study included 108 diabetes（56 with micro-circulative pathological changes ）and 58 normal controls with similar age and sex.All the participants underwent RT-3DE to assess LA volume and mechanical function.Plasma NT-proBNP and GHbA1 are tested. Results: （1）The left atrial diameter was much higher in DM2 group compared with controls and DM1 group（P<0.05）,while there was no significant difference between DM1 and control group；The E/e and IVRT were increase in both DM groups （P<0.05）， IVRT was higher in DM2 group compared with DM1 group（P<0.05）. （2）The LAVmax、LAVmin、LAVp、LAVImax、LAVImin、LAEFt and LAEFa were all found to be significantly higher in DM2 group when compared with controls,which reflect LA volume 、reservoir and pump functions, and that only LAVmax、LAVp、LAVImax、LAVIp and LAEFa were increased in DM1 group.Further more, LAVImax、LAVIp、LAEFt and LAEFa in DM2 group are higher when compared with DM1 group（P<0.05）. （3）There were strong relationship between LAVI and E/e,and positive with NT-proBNP,only weak with GHbA1. Conlusions:LA mechanical functions and volumes are already impaired in diabetes patients，and it is more obvious in patients with micro-circulative pathological change.RT-3DE may be a useful way for assessment of left atrial function in diabetes patients.