This study was conducted at the farm of agriculture college (Abu Jarash), Damascus university to determine the impact of time and depth of adding phosphorus on it's availability in calcareous soil cultivated with corn during 2011 and 2012 seasons. Super phosphorus fertilizer was added to the soil at three different depths (0, 10 and 20 cm), while the control spot left without fertilizer addition. Soil samples were taken for analysis of available phosphorus (P) from 12 replicates at different depths 0-10, 10-20, 20-30, 30-40 cm with two samples for every depth at zero time, 15, 30, 45, 60 and 90 days during the growing corn. Results indicated that the available phosphorus increased directly in all samples after cultivation, with a marked value recorded at all depths after 15 days of cultivation. This concentration began decreasing gradually with a constant rate in time in all transactions and reached 50% after 90 days of cultivation. It was also observed that available phosphorus was higher at the two depths, 0-10 and 10-20 cm and after 15 days of post- corn cultivation and followed by zero time and it was found that the best concentration was observed at depth extended from 0 to 20 cm in the treatment of adding fertilizer at depth of 10 cm and time of sampling was 15 days of cultivation.