There are a lot of conflicts of interest in scientific activities because of their intermingling with financial interests.Conflicts of interest mean that when the investigators work for two institutions at the same time and get individual benefits,the interest factor will affect or endanger them to make right,objective and just judgement,which includes the administrative conflict,actual and latent conflict,conflict of commitment etc.The seeds of conflict of interest are all kinds of personal gains.The tool of conflict of interest is investigator's bias that produced by interests.These conflicts of interest can be controlled by self-control,peer review,government control,institutional policies and procedures,content and process of disclosure and sanctions.