Two experiments were conducted with 4‐wk‐weaned pigs to determine whether sucrose and glucose can substitute lactose supplemented in diets for early‐weaning pigs. In EXP. 1, a total of 120 pigs with average weight of 8.0 kg were allocated to one of five experimental diets. The control diet was formed with corn‐soybean meal based without inclusion of antibiotic. The treatment diets were achieved with 6.0% corn in control diet being replaced on a weight basis by lactose, sucrose, glucose or cornstarch. In EXP 2, 25 pigs were used in a balance trial to examine the effect of addition of different sugars on crude protein (CP) and gross energy apparent digestibility. The dietary treatment was achieved similar in EXP. 1, except that the 0.3% chromic oxide was included to act as an indicator for determine the apparent digestibility. In spite of type, sugars’ addition did not affect the ADFI (P > 0.05). And pigs fed lactose and glucose supplemental diets showed the similar ADG and feed efficacy and were superior to control, sucrose and cornstarch (P < 0.05). Similarly, the DM, CP and gross energy apparent digestibility of lactose and glucose treatment showed a tendency greater than the control, sucrose and cornstarch, though no statistical difference (P > 0.05). Sucrose treatment caused a superior serum Ca and glucose levels than control and cornstarch (P < 0.05), and the other serum biochemical indexes maintained unchanged by the sugar’ treatment (P > 0.05). Lactose addition kept the lactase activity at a high level, almost two times of the other groups. These results suggest that glucose, not sucrose, can instead of lactose employed in post weaning diets without supplement of antibiotic.