Quantum anomalous Hall (QAH) effect is the latest member getting involved into Hall effect family, which was realized in topological insulator (TI) in recent years [1,2] and was regarded as a green application of TI-based spintronic device. Magnetism is the key to quantize the anomalous Hall effect with a dissipationless spin transport dynimics on the surface state of TI. In this scope, two types of magnetic TI triggered by means of magnetic doping (Cr) and magnetic adlayer (CrSe) are demonstrated along with their deterministic threshold to achieve QAH state. With respect to magnetic doping, we found the superparamagnetic domains with a complex magnetic coupling naturally developing in the thin TI (<8nm), leading to the suppression of QAH. Upon increasing the thickness of TI (≧8nm), superparamagnetism vanished with a robust ferromagnetism and the QAH could be fully restored. The other branching strategy to magnetically polarize TI was by using a magnetic adlayer via the so-called magnetic proximity effect (MPE). We found an antiferromagnetic insulator (AFI), CrSe, yielding large uncompensated spin was capable of bringing ferromagnetic order into TI. However, the magnetism of TI, MPE as well, could be only activated when the CrSe was grown on top of it but was absent in the inverse structure. X-ray magnetic spectroscopy and first principle calculation both suggest MPE could be activated upon the interface of CrSe was terminated by Cr, rather than Se. Based on the results of the two types of magnetic systems, we conclude the magnetic homogeneity and interface property play a significant role of mediating the QAH channel, which should be seriously considered for the future TI-based spintronic device.