  We study the refined R\'{e}nyi negativity in the matrix model of
Jackiw-Teitelboim (JT) gravity. We first consider the JT gravity with dynamical
branes, which serves as a toy model of the evaporating black hole. By including
the backreaction of branes, we find that the refined R\'{e}nyi negativity
monotonically decreases at late time of the evaporation. Next we define a novel
quantity, which we call ``capacity of negativity,'' as a derivative of the
refined R\'{e}nyi negativity with respect to the replica number. We find that
the capacity of negativity has two peaks as a function of time, which comes
from the exchange of dominance of the different types of replica wormholes.
