On the basis of Conceptual Metaphor Theory proposed by George Lakoff and Mark Johnson, this paper conducts a cognitive analysis of conceptual metaphors in Donald J. Trump’s State of the Union Address in 2020, aiming to explain the metaphors in the State of the Union Address, reveal the political intentions hidden behind the metaphors, and construe the relationship between politics and metaphor. It is found that the metaphors in this State of the Union Address are: CONFLICT metaphors, BUILDING metaphor, JOURNEY metaphors, ORIENTATIONAL metaphors, and PLANT metaphors. Through the analysis, this paper concludes that conceptual metaphor has the function of persuading the masses and shaping the image of politicians. At the same time, this paper also finds that politics restricts the choice and application of metaphor.