The objective of this study was to obtain the energy requirement of water buffalo in early lactation by factorial method. Thirty healthy water buffalo in early lactation with similar milk yield in the last lactation period and parities (2 or 3) were randomly divided into 3 groups with 10 heads in each group. Water buffalo in the 3 groups were fed concentrates with 3 energy levels and an equal crude protein level (13.5%), in which the net energy values for lactation were 6.0, 6.6 and 7.2 MJ/kg, respectively. The preliminary trial period lasted for 15 d, and the trial period lasted for 30 d. Three heads in each group were selected for a 7-day digestive metabolism test and a 3-day gaseous metabolism test on the 24th and 28th day of the trial period, respectively. The results showed as follows: the net energy for maintenance (NEm) was calculated by energy intake and heat production, NEm=263.40 kJ/(W0.75·d)×120%=316.10 kJ/(W0.75·d); the milk energy was 4.4 MJ/kg, the transfer coefficient of normal milk and fat corrected milk (FCM) was 1.51 during the digestive test. Thus, the production of 1 kg FCM required 2.915 MJ of net energy. According to the principle of factorial method, the requirement for net energy of water buffalo in early lactation can be estimated by the following equation: NE (MJ/d)=0.316W0.75＋0.290 7ΔW×W0.75＋2.915FCM (NE is the net energy, W0.75 is the metabolic weight,ΔW is the daily changing of body weight, and FCM is the fat corrected milk yield).［Chinese Journal of Animal Nutrition， 2011， 23（6）：950 -955］