This experiment was conducted to determine the effects of reducing the ratio of dietary lysine (Lys) to net energy (Lys/NE) on performance and meat quality in finishing pigs. One hundred and forty Yorkshire pigs with initial average body weight of (30.0±1.6) kg were randomly allotted to 5 treatments (4 replicates per treatment and 7 pigs per replicate) based on their body weight and sex. During the 30～61 kg phase, all pigs were fed the same diet. During the finishing phase, pigs in each treatment were randomly fed with one of five diets: control, low Lys-1, low Lys-2, low protein-1 and low protein-2 (CP levels were 15.20%, 15.02%, 15.11%, 12.73% and 10.10%, respectively; Lys/NE ratios were 0.72, 0.58, 0.46, 0.58 and 0.46 g/MJ, respectively). The results showed that the low Lys-1 and low Lys-2 treatments had significantly increased average daily gain (ADG) and intramuscular fat (IMF) content of pork in finishing pigs (P<0.05) compared with control, but simultaneous decrease of CP level had no significant difference on ADG and IMF of pork compared with control (P>0.05). Different treatments had no significant effect on average daily feed intake, F/G, alive weight, dressing percentage, pH1 h, pH24 h, shear force and drip loss (P>0.05). Low Lys-2 and low CP-2 treatments had lower meat color value than control diet (P<0.05). No significant effects on plasma urea nitrogen (PUN) content were observed among other treatments (P>0.05), except that plasma UN content in low protein-2 treatment was significantly lower than that in control (P<0.05). Compared with control, pigs fed the low Lys-1 and low Lys-2 diets had lower plasma IGF-Ⅰ content (P<0.05), while pigs fed low protein-1 and low protein-2 diets had higher plasma IGF-Ⅰ content (P<0.05). The results indicated that Lys/NE in diet decrease from 0.72 to 0.46 g/MJ could improve IMF content of finishing pigs; Lys/NE in diet reaching 0.46 g/MJ with protein level being 10.1% could decrease feed conversion rate of finishing pigs.［Chinese Journal of Animal Nutrition, 2010，22（4）:856-862］