The construction of high-standard cropland can improve the quality of arable land, which is a strategic base for guaranteeing national food security. Based on the quasi-natural experiment of the high-standard cropland construction policy, the effect of high-standard cropland construction policy on the decision-making of grain cultivation on farmland is examined by adopting the continuous difference-in-difference method. The result shows that the high-standard cropland construction policy significantly increases the the proportion of grain sown area and produces a "grain-oriented" effect. The conclusion still holds after a series of robustness tests. The dynamic effect analysis reveals that as the construction of high-standard cropland continues, its effect of promoting the "grain-oriented" effect on cropland continues to increase. Heterogeneity analysis shows that the high-standard cropland construction policy is more effective in promoting the "grain-oriented" cultivated land in plain areas, higher agricultural dependent areas, and larger cultivated land areas. Mechanism analysis indicates that the high-standard cropland construction policy influences the "grain-oriented" cultivated land by land scaling, service scaling and technological progress. Further research illustrates that the development of cooperatives and agricultural credit investment can strengthen the promotion effect of the high-standard cropland construction policy on the "grain-oriented" cultivation of arable land.