[Objective] The study aimed to investigate the grain filling characteristics of Mianyang 26 and its sister lines under field soil drought condition.[Method] Under the water stress,the grain filling processes of ten dominant winter wheat varieties of Mianyang 26 and its sister lines were modeled with Logistic equation and a series of inferior parameters were conducted.The relationship between grain filling parameters and grain weights was analyzed using correlation,stepwise regression and path coefficient an...