Abstract: Abstract: (Objctive)This experiment was carried out to provide reference for reasonable selection of pH and phosphate levels when phosphorus absorption experiment in vitro with Chicken small intestine by investigate the effects of phosphate levels and pH in culture medium on absorption of Pi by incubating everted intestinal sacs of broilers. (Method)Two experiments of single-factor four-treament were used. Sacs of duodenum,jejunum and ileum from 48 male broilers at the age of 30 days were random distributioned to eight treaments, each treament was assigned six replicates, one replicate was assigned one sac, culture 50min under condition of 40℃. (Result)The results showed that: pH and phosphate levels in medium have obvious effect on the phosphorus uptake. The phosphorus uptake of gut sacs was increased linearly when pH value between 5.0 and 7.0. Compared with pH 5.0, the intestinal absorption of phosphorus increased significantly (P＜0.01). But the absorption of phosphorus began to reduced when pH up to 8.0; Phosphorus uptake and phosphorus content was positively correlated when phosphorus content in medium among 50μg/ml, 1000μg/ml and 200μg/ml.But the phosphorus uptake of the duodenum and jejunum began to reduced when the phosphate level up to 400μg/ml. (Conclusion)The results suggest: the optimum pH is 6.0～7.0 and phosphorus content can not exceed 200μg/ml in culture medium when assesse feed available phosphorus with method of everted intestinal sacs.