The aim of this study was to investigate the growth performance of growing and finishing pigs, and carcass characteristic and meat quality of finishing pigs fed with low crude protein (CP) diet formulated by net energy system in commercial pig farm. In the growing (experiment 1) and finishing stage (experiment 2), two hundred and sixteen Duroc×Landrace×Yorkshire growing (30~55 kg) and finishing pigs (50~100 kg) were all randomly allocated to 2 groups of a low CP diet and a normal CP diet group, respectively (each group 6 replicates and 18 pigs per replicate). Thirty finishing pigs were slaughtered when experiment 2 finished. The results showed that average day gain, average day feed intake, and F/G of growing and finishing pigs received the low CP diet were all significantly lower when compared with normal CP group (P>0.05); but the cost of each increased kilogram weight of growing pigs was significantly decreased by 6.80%/kg compared with the pigs received the normal CP diet (P<0.05), and that of finishing pigs was significantly decreased by 6.80%/kg (P<0.05). Except that water loss rate of low CP diet group was significantly higher than that of normal CP group (P<0.05), carcass characteristics and meat qualities in low CP diet group had no significant difference compared with that in normal CP group (P>0.05). In conclusion, low CP diet formulated by the net energy system in commercial pig farm could achieve similar performance for growing or finishing pigs and carcass characteristic and meat qualities for finishing pigs compared with normal CP diet, and decrease cost of per increased kilogram weight.［Chinese Journal of Animal Nutrition, 2010，22（3）:557-563］