Objective To investigate the changing trend of hemoglobin （Hb） and related influencing factors in patients with liver failure after artificial liver support system （ALSS） therapy. Methods A total of 106 patients with liver failure who were hospitalized and received ALSS therapy in our hospital from January to December 2018 were enrolled and analyzed in terms of clinical data and red blood cell parameters such as Hb， mean corpuscular volume （MCV）， mean corpuscular hemoglobin （MCH）， mean corpuscular hemoglobin concentration （MCHC）， and red blood cell distribution width-coefficient of variation （RDW-CV）. A one-way repeated-measures analysis of variance was used for comparison of continuous data with repeated measurement between groups， and the paired t-test was used for comparison between two groups. The Kruskal-Wallis H test was used for comparison of continuous data with skewed distribution between multiple groups， the Mann-Whitney U test was used for further comparison between two groups. Univariate and multivariate linear regression analyses were used to identify the influencing factors for the reduction in Hb after ALSS therapy. Results The 106 patients with liver failure received 606 sessions of ALSS therapy， and Hb was measured for 402 sessions before and after treatment. There was a significant reduction in Hb after ALSS therapy in the patients with liver failure （97.49±20.51 g/L vs 109.38±20.22 g/L， t=32.764， P<0.001）. Longitudinal observation was further performed for 14 patients with liver failure， and the results showed that the level of Hb was 108.50±21.61 g/L before the last session of ALSS therapy， with certain recovery compared with the level of Hb （103.14±19.15 g/L） on the second day after ALSS， and there was an increase in Hb on day 3 （102.57±21.73 g/L） and day 7 （105.57±22.04 g/L） after surgery. The level of Hb in patients with liver failure on the second day after ALSS decreased with the increase in the number of ALSS sessions （F=8.996， P<0.001）， while MCV and MCH gradually increased with the increase in the number of ALSS sessions （F=9.154 and 13.460， P=0.004 and P<0.001）， and RDW-CV first gradually increased and then gradually decreased （F=4.520， P=0.032）； MCHC showed fluctuations with no clear trend （F=0.811， P=0.494）. The multivariate linear regression analysis showed that the duration of ALSS therapy， the mode of ALSS therapy， and initial treatment were independent risk factors for the reduction in Hb after ALSS therapy. Conclusion ALSS therapy can influence the level of peripheral blood Hb in patients with liver failure， and patient blood management should be strengthened for patients with liver failure who are receiving ALSS therapy.