Abstract: With application of modern genetic theory and breeding technique, the paternal and maternal lines used for crossing have been established. The paternal line was developed from inbreeding, its inbreeding coefficient was 38-39%, While the maternal line was selected from generation among closed flock. The amount of egg laid by duck with age in 500days was as much as 266-276 in paternal line and 285-296 in maternal line. By mating between two lines and determining their combining ability of all combinations, it showed that the egg amount of optimum combination duck aged in 500 days was maximum to 329-344 which was 19 -16% above its parental lines. After establishment of proliferative system, there were 870, 000 ducks bred during 1988-1991 and the egg amount laid by 500 days age duck among these large scale was averaged to 305-310. In addition to breeding, It has been approached that: activity of enzyme extracted from duck embryo histological medium as standard for early line selection; main hereditary character data estimated as ecomonic index; the genetic feature for indio-shell egg heredity in duck breed; and the energy and protein necessity for these egg-laying ducks.