The invention discloses a continuous filament reinforced thermoset cell structure 3D printing device and a preparing method thereof. A printer working table face is arranged inside a vacuum heating box, the vacuum heating box is arranged with a vacuum pump, a rotation transversely-moving printing table is placed on the printer working table face, and a printing grating testing piece is placed on the rotation transversely-moving printing table; a first printing part and a second printing part are coiled on a first feeding roller and a second feeding roller through resinoid containing fiber bundles correspondingly, and the first printing part and the second printing part are connected with a first printing head and a second printing head through a 3D printer control device by means of the resinoid containing fiber bundles correspondingly; and the 3D printer control device is connected with control software. According to the continuous filament reinforced thermoset cell structure 3D printing device and the preparing method, dies are not needed, automation in the whole process is achieved, and forming of various complex form gratings can be achieved.