This paper is dedicated to studying the Choquard-type equation \( \left \{ \textstyle\begin{array}{l} - \Delta u + V(x)u = ( {{I_{\alpha }} * {{\left | u \right |}^{ p}}} ){ \left | u \right |^{ p - 2}}u + \lambda {\left | u \right |^{q - 2}}u, \\ u \in H^{1} ({\mathbb{R}^{N}}), \end{array}\displaystyle \right . \) where $N\geq 3$ , $\alpha \in \left ({0,N}\right )$ , $1< q<2^{*}: = \frac{{2N}}{{N - 2}}$ (the critical Sobolev exponent), $p=\frac{N+\alpha }{N-2}$ is the upper critical Hardy-Littlewood-Sobolev exponent and $I_{\alpha }$ is the Riesz potential. When the reciprocal of the potential V is integrable, we establish the existence of solutions to the above problem for both sublinear and superlinear cases by means of the variational methods.