The experiment was conducted to study the effects of digestible energy (DE) and true digestible lysine (Lys) on performance, composition of gestation tissue and hormone levels of primiparous sows during early gestation (mating-on day 84 of gestation), and to find out optimal requirement for energy and Lys content of primiparous sows during early gestation. The best saturate-D regressive design of 2 factors (DE and true digestible Lys) and 4 levels was employed, and thirty-six at 7-8-month-old CB line sows of Yurong Ⅰ multiple cross system with average weight of (123.26±5.69) kg were allocated to 6 groups with 6 replicates of 1 sow. The sows were penned individually with restricted feeding, and the experiment lasted for 84 days. The results showed that maternal body gain tend to be increased with DE and true digestible Lys increasing during early gestation. Ascending DE levels significantly decreased the number of live litter (P<0.05) and increased the number of dead fetus and mummy foetus on day 84 of gestation (P<0.01). There were no significant effects of DE and true digestible Lys on gross weight of gestation tissue, and content of crude protein, ether extract and amino acides (P>0.05). During early gestation, concentration of progesterone in serum of sows declined, while concentration of insulin rised with DE increasing; both of DE and true digestible Lys content had no effects on the concentration of luteinizing hormone in serum (P>0.05). In conclusion, the proper content of DE and the true digestible Lys during early gestation was 12.50 MJ/kg and 0.69% for litter weight of primiparous sows.［Chinese Journal of Animal Nutrition, ２００9，２1（5）:625-633］