The multi-messenger observations of the binary neutron star (BNS) merger event GW170817/GRB170817A/AT2017gfo have provided significant insight in the equation of state of dense matter. Apart from the tidal deformability measurement which puts constraint on the NS radius, the properties of the merger remnant could also be interpreted from the observations and then be used to constrain the maximum mass of a cold non-rotating NS. Various results have been obtained after the observation, most of which by applying an oversimplified assumption that the NS collapses to a black hole at the mass shedding limit. Here, I will introduce our new analysis which takes into account dissipation processes such as neutrino and post merger gravitational wave emissions and based only on conservation laws of baryonic mass, energy and angular momentum. A more reliable constraint on maximum mass of NS has been obtained as 2.1~2.35 solar masses with our new approach.
