Aim To observe the mid-term and long-term effectiveness of cardiac resynchronization therapy （CRT） optimized by AV/VV delay for patients with congestive heart failure （CHF）. Methods Nineteen patients with refractory heart failure received CRT device implantation. Pacing parameters were detected, and AV/VV interval was optimized according to the guidance of echocardiography during follow-up period. The effect of CRT was evaluated in terms of echocardiography, tissue Doppler, ECG and brain natriuretic peptide （BNP） during follow-up period. Results The best optimized AV delay was between 120 ms and 180 ms （158.33±19.46 ms）, the best optimized VV delay was between 4 ms and 28 ms （15.83±7.12 ms）, clinical symptoms were improved. 6 minutes walking distance was significantly increased （255.71±21.58 m vs. 397.37±11.35 m, P<0.05）. The QRS interval was decreased （138.79±16.06 ms vs. 105.53±8.80 ms, P<0.05）. Left ventricular end diastolic diameter （LVEDD） after implantation was significantly reduced compared with pre-implantation （73.53±9.41 mm vs. 54.11±3.41 mm, P<0.05）, left ventricular ejection fraction （LVEF） was increased （31%±3% vs. 58%±6%, P<0.01）. Aortic velocity time integral of mitral regurgitation （AVTI） was increased （14.69±1.48 vs. 20.52±1.18, P<0.05）, plasma BNP level decreased （1069.02±501.85 ng/L vs. 81.26±31.51 ng/L, P<0.05）. The intra-ventricular and inter-ventricular asynchrony indexes were significantly improved. Conclusions Dynamical optimization of AV/VV delay in CRT improved the hemodynamic of the patients with CHF and enhanced the mid-term and long-term effect of CRT.