The invention disclose an activated cell absorber which comprises absorption membrane supporting frames, a shell, an absorption membrane, an absorption membrane inner supporting core and end covers, wherein the absorption membrane is wrapped with the shell, the absorption membrane inner supporting core is wrapped with the absorption membrane, the two ends of the absorption membrane inner supporting core are connected with the absorption membrane supporting frames respectively, an end cover is arranged on the outer side of each absorption membrane supporting frame, the end covers are connected with the two ends of the shell respectively to form a closed cavity, the absorption membrane supporting frames, the absorption membrane and the absorption membrane inner supporting core are all located in the closed cavity, a blood inlet is formed in one end cover, and a blood outlet is formed in the other end cover. According to the activated cell absorber, the existing filtering method is replaced with the absorbing method, and therefore excessive elimination, damage and activation of leukocyte can be avoided. The invention further discloses a control system and method of the activated cell absorber. Safety, reliability and high intelligentization degree are achieved.