Obesity and diabetes mellitus (T2DM) are metabolic related diseases with high incidence rate at present. Obesity is considered as one of the risk factors of T2DM. At present, the interaction mechanism between obesity and T2DM has not been clearly studied.Adipose tissue is an endocrine organ related to the pathophysiology of obesity and its complications. Adipose tissue can not only store a lot of energy, but also secrete many hormones, oxidative stress and inflammatory factors, which may be related to the occurrence and development of T2DM. Under long-term and low-dose stimulation, the sustainable low grade inflammation of fat is considered to be an important mechanism for the occurrence and development of obese T2DM. Therefore, this paper mainly summarizes the research progress of low grade fat inflammation in obese T2DM.