The pursuit of more efficient and safer treatments is a major challenge in preclinical nanoparticle-mediated magnetic hyperthermia research. Herein, Mn_0.5Zn_0.5Fe₂O₄/MWCNTs (MZFC) nanocomposites were synthesized via the chemical co-precipitation method for cancer treatment. The experiments interestingly demonstrated that the saturation magnetization (Ms) increases first and then decreases by doping a small amount MWCNTs (Multi-walled carbon nanotubes), which reaches the maximum value of 90.6 emu/g when the doping amount is 1.0 wt%. Furthermore, the induction heating ability of MZFC with good magnetic induction heating properties when the calcination temperature (T_CA) of the samples is 700 ℃. Surprisingly, although the magnetic saturation of MZFC-2–700 (MZFC-m-n, where m, n present the content of MWCNTs and calcination temperature, respectively) and MZFC-4–700 is lower than that of MZFC-1–700, the ∆T and SAR values of MZFC-2–700 and MZFC-4–700 are both larger than that of MZFC-1–700 in the low-frequency range (238 ~ 260 kHz). However, further increasing the frequency to the high-frequency range (300–380 kHz) presents the opposite conclusion. The same conclusion was also confirmed in tissue-mimicking phantoms, which suggests Mn_0.5Zn_0.5Fe₂O₄/MWCNTs could obtain the temperature suitable for tumor treatment at a lower magnetic field frequency, thus avoiding the harm of high-frequency magnetic field to human body from eddy current. In vitro experiments verified, MZFC provides the potential to serve as biological materials for magnetic hyperthermia and good biocompatibility. Therefore, these magnetically responsive nanocomposites could be a promising platform for hyperthermia treatment.