High-pressure solid-state metathesis (HPSSM) reaction is an effective route to novel metal nitrides. A recent advance in HPSSM reactions is presented for a number of examples, including 3d transition metal nitrides (ε-Fe₃N, ε-Fe_{3_x}Co_xN, CrN, and Co₄N_x), 4d transition metal nitrides (MoNx), and 5d transition metal nitrides (Re₃N, WN_x). Thermodynamic investigations based on density functional theory (DFT) calculations on several typical HPSSM reactions between metal oxides and boron nitride indicate that the pressure could reduce the reaction enthalpy DH. Highpressure confining environment thermodynamically favors an ion-exchange process between metal atom and boron atom, and successfully results in the formation of well-crystalized metal nitrides with potential applications.