Frame structure for ceiling lighting device

A frame structure for ceiling lighting device, comprising:

• a plurality of first frame bars, wherein each of the first frame bars comprises a first frame bar body and a first chamber structure disposed on one side of the first frame bar body;
• a plurality of second frame bars, wherein each of the second frame bars comprises a second frame bar body and a second chamber structure disposed on one side of the second frame bar body;
• and
• a plurality of corner braces, wherein each of the corner braces comprises a first extension arm inserted into an opening at one end of the first chamber structure of one of the first frame bars and a second extension arm inserted into an opening at one end of the second chamber structure of one of the second frame bars, whereby the first frame bars and the second frame bars are combined with each other;
• wherein each of the corner braces further comprises a L-shaped plate, an upper cover and a lower cover, wherein the upper cover and the lower cover are respectively disposed at a top and a bottom of the L-shaped plate, wherein the L-shaped plate comprises a first portion and a second portion perpendicular to each other, and the first extension arm and the second extension arm are respectively disposed at the first portion and the second portion, wherein the first extension arm comprises a first supporting arm having a first central hole and a first fixation portion having a first snap-fit hook, wherein the first fixation portion is disposed in the first central hole and connected to the first supporting arm, wherein any one of two ends of the first frame bar body of each of the first frame bars is provided with a first installation hole and the first snap-fit hook is corresponding one of the first installation holes, wherein the first frame bars, the second frame bars and the corner braces are made of plastics.