Scientificity was emphasized in researches on diabetes mellitus in integrated traditional Chinese and western medicine abroad. In clinical researches, random and double-blind method, placebo control and auto-cross-over experiment were employed, and the diet, activity, drug dosage and body weight were under strict control, although such kind of researches was rare. During the past few decades, there were also some good achievements in the researches on diabetes mellitus in integrated traditional Chinese and western medicine in China, but most of the researches were duplicated work at low level. There existed some problems, such as the selection of investigated objects, control of the facts besides of the drugs, randomized grouping, blind method, auto-cross-over control, integrated research of multi-center, selection of indexes, methods of index detection, selection of complex prescription, single drug or monome, animal model, etc. The scientificity of the researches in China should be further improved.