Mechanical properties of Hydrogenated Boron Nitride Nanotubes (HBNNTs) were predicted using Molecular Dynamic (MD) simulations. Five armchair BNNTs with different diameters ranging from 0.542 nm to 5.56 nm were hydrogenated on all Nitrogen atoms in their structures. Energy minimization and geometry optimization were performed. MD simulations were then conducted on HBNNTs using ensemble NVT (fixed number of atom, volume and temperature) and NPT (fixed number of atom, pressure and temperature). The Young`s Modulus was obtained using a linear regression to extrapolate the data to the theoretical density of the tubes. MD simulations results show that there is a decrease in Young`s Modulus of BNNTs`when H atomsbonded to all Nitrogen atoms in the system.