Junfeng Li "On the low regularity of the fifth order Kadomtsev-Petiashvili I equation" We consider the fifth order Kadomtsev-Petviashvili I (KP-I) equation. We introduce an energy space which is a nature function space to consider the well-posedeness of the initial problem (IVP) of the fifth order KP-I equation. For the third order KP- I equation, it has been proved that one can not obtain the well-posedness in the Energy space by using the Picard interation argument. We will present that the Picard interation argument work in our case. Since the fifth order dispersive function can help us to recover a full derivative while in the third KP-I equation, one can only recover a half derivative. We obtain the local well-posedness of IVP of the fifth order KP-I equation in some low regularity energy space and global well-posedness for the general energy space.