Let $(G,σ)$ be any signed planar graph. We show that the Alon-Tarsi number of $(G,σ)$ is at most 5, generalizing a recent result of Zhu for unsigned case. In addition, if $(G,σ)$ is $2$-colorable then $(G,σ)$ has the Alon-Tarsi number at most 4. We also construct a signed planar graph which is $2$-colorable but not $3$-choosable.