In order to screen new varieties of suitable mechanical grain harvesting maize, the main agronomic traits, stem traits and harvesting traits of maize in the harvest period were studied through taking 18 main varieties and newly-tested varieties in Liaoning Province as materials. It obtained the following results. Between different maize varieties, there was significant difference in the mechanical grain yield, and the quality difference was also significant. Ten test varieties including Tieyan 818 and Danyu 311 obtained higher yield than the control variety. The moisture content at harvesting was 26%-30.4%, the average moisture content was 28.22%, the average breaking rate was 6.52%, the average impurity rate was 1.91%, and the average yield loss rate was 6.33%. Danyu 212, Tieyan 58, Dika 516 and Danyu 801 had higher yield, and the grain moisture content, broken rate, impurity rate and yield loss rate were relatively low, so these varieties are suitable for promoting mechanical harvesting. Among the 8 traits surveyed, the traits positively correlated with yield were the percentage of broken stalks, degree of lodging, moisture content at harvesting, and percentage of kernel weight in ear weight, and traits negatively correlated with the yield included plant height, ear height, percentage of bare plants, and degree of lodging. Therefore, high moisture content is the main problem in the mechanical grain harvesting of maize, it is required to properly select early maturing varieties.