Based on the study of apoptosis-induced and anti-proliferation behavior of silver nanoparticles (AgNPs) on cancer cells, the attractively therapeutic effect and potential application of AgNPs in anti-cancer field was gradually revealed. Here we investigated the effect of 10 nm silver nanoparticles (AgNPs) on human glioma U251 cells upon the combination treatment of ionizing radiation (IR) treatment with magnetic hyperthermia (MHT). AgNPs showed both radio and thermo sensitivity on U251 cells from the surviving fraction curve. Besides, we found both X-rays and heat could enhance the content of cells uptake of AgNPs. As the amount of intracellular AgNPs accumulated, the apoptosis rate of U251 cells enhanced. Furthermore, we established a simplified model for calculating cell survival rate and demonstrated that after RT, MHT and RT combined with MHT, AgNPs could significantly inhibited cancer cell proliferation. Our results revealed that AgNPs could have a potential application in enhancing effect of RT with MHT combination therapy induced killing of cancer cells.