Magnetic Resonance Imaging (MRI), comprising of static magnetic fields, radio-frequency (RF) fields and timevarying gradient magnetic fields, is a diagnostic technique that a physical-effect is being transformed an image information for human after the immigrated electromagnetic energy imports ones. The electro magnetic fields may possibly have some risks for human health, such as nerve stimulation of gradient fields and thermal-effects of RF fields. During recently decades, FDA of USA has given a safety alert of MRI related death of patients with aneurysm clip, a public health notification of MRIcaused injuries in patients with implanted neurological stimulators and an advisory of risk of burns during MRI scans from transdermal drug patches with metallic backings. Nevertheless, MRI can be safe under a limited intensity electromagnetic fields. This review  reports the bio-effects and health risk associated with three fields and some national and international standards about the limited electromagnetic fields in MRI.