A detachable fixing mechanism and a related electronic device can be used to fix an object on a bracket. The detachable fixing mechanism includes a positioning pin and an actuating component. The positioning pin is disposed on the bracket, and includes a supporter whereon an annular sunken slot is formed. The supporter can pierce through an opening on the object. The actuating component includes a constraining slab portion and a contacting slab portion. The constraining slab portion includes a first engaging structure engaged with the annular sunken slot to constrain a movement between the positioning pin and the actuating component. The contacting slab portion flexibly bends from the constraining slab portion. The contacting slab portion includes a second engaging structure connected to the first engaging structure and slidably disposed on the supporter. The contacting slab portion can move relative to the supporter to press the object on the bracket.