Abstract: AIM To explore the dissimilarities of left and right atrial(LA and RA) functions in normal subjects using two-dimensional speckle tracking echocardiography(2DSTE). METHODS 2D images were acquired from the apical four- and two-chamber view in 148 normal subjects. Stain and strain rate were obtained, respectively, in ventricular systole, early diastole and late diastole using TomTec software. Strain parameters(εs, εe, εa) corresponded, respectively, to atrial reservoir, conduit and booster pump JPfunctions and the strain rate parameters included SRs, SRe and SRa. RESULTS Vmax(43±11) ml vs.(38±10) ml, reservoir function parametersfilling volume=(30±9) ml vs.(21±7) ml; expansion index=(193±92)% vs.(138±79)%; diastolic emptying index=(63±11)% vs.(54±12)% and conduit function parameterspassive emptying index=(30±10)% vs.(25±13)% of LA were significantly higher than those of RA. Contrarily, deformation indicators of RA strain and strain rate parameters were significantly higher than those of LAεs(59±8)% vs.(43±6)%; SRs(2.5±0.7)/s vs.(2.3±0.7)/s; εe(32±10)% vs.(23±5)%; εa(-29±11)% vs.(-20±3)%. CONCLUSION Dissimilarities of left atrium and right atrium exist in normal subjects. 2DSTE can be used to objectively evaluate left and right atrial functions, which provides a research foundation for studies on atrium functions in different diseases.