Abstract: The study aimed to accelerate the progress of lean pig breeding research in China and to develop economic weight that meet the current status of lean pig breeding in China. This study was conducted to select target traits suitable for the current Duroc-Landrace-Large White crossbreeding system in China based on the current breeding status of Duroc-Landrace-Large White crossbreeding pigs in China. The production process of pigs was simulated based on the bio-economic model, and the cost and income at each stage of the production cycle were calculated. The marginal benefits of the target traits were first calculated using the difference method, and then the economic weight of each breeding target trait was obtained by correcting for the genetic standard deviation of each trait. The results showed that it mainly included litter size born alive, sow weaning interval, feed conversion efficiency, days at 100 kg body weight, and backfat thickness at 100 kg body weight in the reproduction, growth and carcass quality traits for lean pig breeding in China at present. Under the existing production level and market conditions in China, the marginal benefits of the above traits were 19.52, -1.07, -286.95, -8.41 and -13.20 yuan, respectively. By calculating the economic weight of different breeds, the relative economic weight of feed conversion efficiency, days at 100 kg body weight, and backfat thickness at 100 kg body weight of Duroc were obtained as 50.42%, 34.50%, and 15.08%, respectively. And the relative economic weight for litter size born alive, sow weaning interval, feed conversion efficiency, days at 100 kg body weight, and backfat thickness at 100 kg body weight for the Landrace and Large White groups were 16.82%, 0.22%, 39.56%, 31.42%, 11.98% and 32.22%, 0.41%, 33.22%, 24.43%, 9.17%, respectively. At present, feed utilization efficiency should be the main target trait for breeding in the breeding process of Chinese lean pigs, and the most suitable trait should be selected for different breeds.

Key words: lean pig, breeding objectives, marginal benefit, economic weight