The aim of this study is to investigate the effects of different humic acid and phosphorus levels on corn plant ( Zea mays L.) growth and P availability in a calcareous soil. Four levels of P (0, 20, 40, 80 $mgkg^{-1}$) and 3 levels of humic acid (0, 250, 500 $mgkg^{-1}$) were used in the experiment. The results showed that the dry weight, plant P concentration, P uptake and residual available P amount increased with humic acid applications, and that the effect of humic acid on the above parameters combined with P fertilisation was higher than that of humic acid alone.