Tw enty pa rent s w ere used in dev elo pment of heino ng cul tiva r series o f soybea n ofw hich Mancha ng jin, Jingsha npu and Zihua 4 w ere ma jo r gene sources of thecultiv ars.Fi f ty tw o percent of the cultiv ars a naly zed in thi s paper contains Manchang jin g ene source, 39% co ntains Jing shanpu gene source and 32% co ntains Zihua 4 gene source. Inthe la ter years th e released cultiv ars o btained, the less g enetic cont ributio n f rom the 3majo r parents. This indicates tha t new g enes w ere co ntinuously intriduced. The g eneraltendency of genetic improvement of majo r ag ronomic trait s in Heinong cultiv ar series isf rom tall- plant, indeterminate and multi- branches to middle heig ht , semi- determinateand few er- branches; mo re- over di sease and lodg ing resistances a re st reng thened.Yield increase o f cul tiv ars dev elo ped in 70s w as achiev ed by increa sing 100 - seed -w eight a nd af ter 80s i t w as achiev ed by increasing pods per plant a nd seed number perpod.