  In present paper, we study the following Schr\"odinger systems
$$\begin{cases} -\Delta u_1+V_1(x)u_1+\lambda_1 u_1=\partial_1
G(u_1,u_2)\;\quad&\hbox{in}\;\R^N,\\ -\Delta u_2+V_2(x)u_2+\lambda_2
u_2=\partial_2G(u_1,u_2)\;\quad&\hbox{in}\;\R^N,\\ 0<u_1,u_2\in H^1(\R^N),
N\geq 1,\\ \int_{\R^N}u_1^2dx=a_1, \int_{\R^N}u_2^2dx=a_2, \end{cases}$$
  where the potentials $V_\iota(x) (\iota=1,2)$ are given functions and the
nonlinearities $G(u_1,u_2)$ are considered of the form $$ \begin{cases} G(u_1,
u_2):=\sum_{i=1}^{\ell}\frac{\mu_i}{p_i}|u_1|^{p_i}+\sum_{j=1}^{m}\frac{\nu_j}{q_j}|u_2|^{q_j}+\sum_{k=1}^{n}\beta_k
|u_1|^{r_{1,k}}|u_2|^{r_{2,k}},~~\ell,m,n\in \mathbb{N}^+_0,
  \mu_i, \nu_j,\beta_k>0, ~2+\frac{4}{N}>r_{1,k}+r_{2,k}, p_i, q_j>2, ~r_{1,k},
r_{2,k}>1,
  i=1,2,\cdots, \ell; j=1,2,\cdots, m; k=1,2,\cdots, n.
  \end{cases}
  $$
  Under some assumptions on $V_\iota$ $(\iota =1,2)$ and the parameters, we can
show the existence of ground state normalized solution $(\lambda_1,\lambda_2;
u_1, u_2)\in \R^2 \times H^1(\R^N, \R^2) $ to the above mass sub-critical
problem for any given $a_1>0,a_2>0$. Here our nonlinearities are general. The
potentials $V_1(x)$ and $V_2(x)$ are also very general such that $\inf
ess~\sigma(-\Delta+V_\iota)>-\infty$, which are allowed to be singular at some
points.
