Obama's Health Care Speech to Congress is aimed at persuading the Congress to accept the health care reform. In virtue of the three aesthetic criteria-logos, paths and ethos maintained by Aristotle delicately，the whole speech is convictive, logical, intelligible and affects the audience that much, as it were, Obama should owe his triumph to rhetoric.The analysis followed is focused on the aspect of logos. In exercising rational appeal, President Obama is appealing to the audience's understanding by resorting to the logical reasoning.