Wittgenstein, in the Tractatus, seems to use the analogy of the projection to illustrate more clearly his semantic theory. This article consists of exposing a possible reading of this analogy from geometry, science where was possibly taken. In this exhibition we show not only the analogy but the possibility of it, through the comparison of the elements of geometry and of the proposition and propositional sign, and show, so how the analogy of the projection can be an excellent resource to explain the theory Tractarian semantics.