  Our purpose of this paper is to study the isolated singularities of positive
solutions to Choquard equation in the sublinear case $q \in (0,1)$
  $$\displaystyle \ \ -\Delta u+ u =I_\alpha[u^p] u^q\;\;
  {\rm in}\; \mathbb{R}^N\setminus\{0\},
  % [2mm] \phantom{ }
  \;\; \displaystyle \lim_{|x|\to+\infty}u(x)=0, $$ where $p >0, N \geq 3,
\alpha \in (0,N)$ and $I_{\alpha}[u^p](x) = \int_{\mathbb{R}^N}
\frac{u^p(y)}{|x-y|^{N-\alpha}}dy$ is the Riesz potential, which appears as a
nonlocal term in the equation. We investigate the nonexistence and existence of
isolated singular solutions of Choquard equation under different range of the
pair of exponent $(p,q)$. Furthermore, we obtain qualitative properties for the
minimal singular solutions of the equation.
