摘要:   In this paper we are interested in the following nonlinear Choquard equation 
 
where  ,  ,  ,   is the upper critical exponent due to the Hardy-Littlewood-Sobolev inequality and the nonnegative potential function   such that   is a nonempty bounded set with smooth boundary. If  , is a constant such that the operator   is non-degenerate, we prove the existence of ground state solutions which localize near the potential well   for   large enough and also characterize the asymptotic behavior of the solutions as the parameter   goes to infinity. Furthermore, for any  , we are able to prove the existence of multiple solutions by the Lusternik-Schnirelmann category theory, where   is the first eigenvalue of   on   with Dirichlet boundary condition.
   
  