Molecular dynamic simulations are conducted to understand the fracture properties of bicrystalline graphene sheets containing high angle grain boundaries. In our simulations, hydrogen atoms are adsorbed at the Stone–Wales defect on the grain boundaries. Hydrogenation of these defects alters the properties of grain boundaries. Using molecular dynamic modeling, the traction-separation laws of grain boundaries before and after hydrogenation are extracted. Our results show that the hydrogen adsorption site and hydrogen concentration are two factors which can significantly impact fracture toughness and strength of grain boundaries. Generally speaking, by increase in hydrogen concentration at the grain boundaries the fracture toughness and strength of the grain boundaries are reduced.