The Meta-analysis has been widely used in the agriculture research abroad and is considered to be a new scientific way for quantitative summarizations of literature data. A meta-analysis was conducted to examine the potential empirical relationships between dietary cation-anion difference (DCAD) and the dry matter intake (DMI). The database was developed from 8 studies in which the effect of the DCAD was observed in the early lactating dairy cows. Observed DMI values were adjusted for study effects. The results showed that, adjusted DMI increased with increasing DCAD (quadratic; P<0.01, R2=0.74), peaking at 298.3 mmol/kg DM; adjusted DMI also increased with the increasing blood HCO-3 concentrations (quadratic; P<0.01, R2=0.91) with peaking at 29.2 mmol/L; adjusted DMI increased with the increasing blood pH, too (quadratic; P<0.01, R2=0.87). These relationships indicated that DMI was closely associated with acid-base status in early lactating dairy cows, and that DCAD affected systemic acid-base balance, which in turn affected voluntary intake of lactating dairy cows.［Chinese Journal of Animal Nutrition, 2010，22（1）:46-50］