Objective To evaluate the diastolic function and relationship between diastolic function and early diastolic synchrony in patients with dilated cardiomyopathy (DCM) by real-time three-dimensional echocardiography (RT-3DE) volume-time curves (VTC) after cardiac resynchronization therapy (CRT).Methods Thirty-nine patients with DCM were enrolled by RT-3DE VTC before and 1 week,6 months,12 months after CRT,draw the left ventricular (LV) 16,12,6 segments LV diastolic early volume standard deviation of the time (Tedv-SD),and with the R-R interval normalized as early diastolic unsynchronized index (DDI) ;draw end-systolic volume (LVESV),LV end-diastolic volume (LVEDV),LV ejection fraction (LVEF) ;and calculate the diastolic peak filling rate(PFR),the ratio of early diastolic volume and enddiastolic volume(EDVearly/EDV).Results LVEDV,LVESV had no significant improvement.Compared with the before and 1 week after CRT,but the improvement was statistically significant after 6 months and 12 months (P ＜0.05,P ＜0.01); LVEF after 1 week,6 months and 12 months were statistically significant (P ＜0.05) ;Compared with before,PFR after 6 months was significantly increased (P ＜0.05),EDVearly/EDV at 12 months after CRT was significantly reduced (P ＜ 0.01); There was a significantly shortened in each segment (Tedv-SD)/R-R 1 week after CRT (P ＜0.01),but the parameters had no obvious improvement later.Correlation analysis:△ DDI and △ EDVearly/EDV reduction was significant positive correlation (r =0.52,P ＜0.01),△DDI and PFR has negative correlation (r =-0.40,P ＜ 0.05),△ EDVearly/EDV and △PFR also had a good relationship (r =-0.56,P ＜0.01).Conclusions The LV synchrony and diastolic function were improved after CRT in patients with DCM; PFR,EDVearly/EDV can be used as evaluation of left ventricular diastolic function effectively targets.