Abstract: 90 DLY cross bred pigs (32.0?1.5 kg) were randomly allocated into 5 groups, 3 replicates per group, 6 pigs in each replicate to investigate the effects of dietary protein and lysine on growth performance and nitrogen excretion in growing pigs. 2?2 factors were designed. Control group was fed with diet of 17.47% crude protein (CP) and 0.80% digestible Lys ( Dly ). 4 treatment groups was fed with diet of 15.46%, 13.49% CP and 0.80%, 0.85% Dly, respectively. The test duration was lasted for 50 days. The results showed that the treatment fed with diet of 15.46% CP and 0.80% Dly has not effect on the growth performance in growing pigs in comparison with others (P>0.05),but compared to the control, urinary nitrogen was significant decreased (PPPP>0.05) compared to the others, urinary and feces nitrogen and total nitrogen was significant decreased (PP>0.05) but at the same time nitrogen excretion is significant decreased in comparison with the diet of 17.47% CP and 0.80% Dly (P<0.05).