With the aim to evaluate the influence of soil hardness to corn growth and calcium absorption, five levels of soil hardness (soil bulk density: 1.1, 1.2, 1.3, 1.4 and 1.5g/cm3) were established in the pot experiment. There was no significant influence of soil hardness to corn growth in the first 15d after seeding, however, it inhibited aboveground corn growth in the following days. Root dry mass and activity both decreased because of the high soil hardness which had a negative effect on calcium absorption. The highest calcium content (1.67%) occurred in the treatment with 1.2g/cm3 soil hardness. The increase of soil hardness caused root activity decrease which led to the decrease of calcium absorption, thus, lower crop resistance to disease and cause in senescence in advance. It was concluded that too high or too low density of soil bulk was disadvantage to the crop growth.