Objective To study the pharmacokinetics of 5-fluorouracil based sustained release chemotherapy.Methods 30 cases with malignant tumor of digestive tract were devided into two groups.Study group received 5-fluorouracil based sustained release chemotherapy,while control group received systematic chemotherapy.Results 5-fluorouracil based sustained release chemotherapy had high apparent volume of distribution,long half time and small area under the curve compared with systematic chemotherapy.Conclusion Sustained release chemotherapy can prolong the regional action time and improve the regional concentration of chemotherapeutic drugs.