Abstract: We implement advanced Riemann solvers HLLC and HLLD together with an advanced Constrained Transport scheme proposed by Gardiner and Stone. Through a series of test problems, we find our new Riemann solver is always superior to HLLE, a standard solver in the numerical relativity community. In its application, we simulate binary neutron star mergers, which have a short-lived remnant, and explored the dynamical mass eject and torus mass dependence of the mass ratio of the binary. By mapping the 3D data of the remnant generated by the new code to the axisymmetric neutrino radiation viscous hydrodynamics code, we follow the evolution of the remnant up to 2-10second. We reveal a comprehensive picture of the mass ejection from the binary neutron star mergers and discuss the possibility of the binary neutron star mergers as the r-process nucleosynthesis site.