Abstract: Single factorial randomized-block design was used to study true digestible phosphorus （TdP） requirement of growing pigs by determining growth performance and serum biochemical indexes. Experimental diets were designed five TdP levels, and the ration of total calcium to TdP was 2:1. The experiment results indicated that (1) we got the equation which was about the variety of ADG of growing pigs along with dietary TdP concentration. (2) The equation describing the relationship between F/G and dietary TDP concentration also was educed; (3) Another equation was educed according to the relationship of serum phosphorus concentration and dietary TdP concentration; (4) The serum ALP activity was falling continually with the rise of dietary true digestible phosphorus concentration (P＞0.05); (5) Serum calcium concentration was influenced by dietary true digestible phosphorus concentration hardly, and the variety trend of serum calcium concentration was accord with serum phosphorus concentration influenced by dietary TdP concentration. It was concluded that the dietary TdP requirement of growing pigs was 0.34% and total Ca requirement was0.68%.

Key words: growing pigs, true digestible phosphorus, calcium, growth performance, serum biochemical indexes