Recessed replaceable LED office lamp

A recessed replaceable LED office lamp, comprising:

• a lamp housing;
• a lampshade;
• and
• a LED light source module being arranged in a lower side of the lamp housing, wherein
• the lamp housing comprises:
• a top plate having first sides that are parallel to each other and second sides that are parallel to each other and perpendicularly connect the first sides of the top plate;
• two side plates respectively extending from the first sides of the top plate inclinedly relative to the top plate, each side plate having first sides being parallel with the first sides of the top plate and second sides perpendicularly connecting the first sides of the each side plate, the second sides of the each side plate extending from respective ends of the second sides of the top plate;
• end plates respectively arranged to close trapezoidal openings formed by the second sides of the top plate and the corresponding second sides of the two side plates;
• a bottom plate formed on and extending outwards from the corresponding first sides of the side plates and a bottom side of each of the two end plates, and an outer edge of the bottom plate being arranged connected to a mounting joist at the time of mounting;
• a hanging plate being movably connected to a lower side of at least one of sides of the bottom plate via a plurality of connecting mechanisms;
• the hanging plate is horizontally slidable outwardly from sides of the bottom plate in a direction away from the top plate by coordinating with the connecting mechanisms,
• a locking mechanism is arranged to lock a position of the hanging plate on the bottom plate after horizontal sliding, and
• the lampshade is inserted in the lamp housing so as to encircle the LED light source module within a containing space composed of the lamp housing and the lampshade.