Peripheral blood lymphocytes (PBLC) isolated from 20 healthy adult volunteers’ blood samples were treated with low-temperature plasma induced by dielectric barrier discharge, in order to investigate the effect of plasma on PBLC. Three experimental groups of PBLC treated with plasma were classified according to their locations laid on the bottom electrode, i.e., the electrode center, the electrode edge (2.5cm away from electrode center) and the electrode outside (on a platform with the same height to bottom electrode and 5.0cm away from electrode center) group, and one control group was without plasma treatment. Three different treatment time intervals were set as 5, 15 or 30s, respectively. Based on the statistical analysis of experimental results, it is revealed that, while the lymphocytes were more than 5cm away from electrode center or the treatment time was less than 5s, their function did not change significantly. Otherwise, the larger the dosage of employed plasma along with longer treatment time was; the more significantly its function reduced. Furthermore, the lymphocytes apoptosis and necrosis caused by Low-temperature plasma maybe result in the degradation of lymphocytes function.