The invention discloses a preparation method for an LED acrylic luminous character. The preparation method comprises the steps that character shell mold preparation is conducted; PMMA slurry preparation is conducted; unsaturated polyester solution preparation is conducted; PMMA slurry and an unsaturated polyester solution are evenly mixed according to a mass ratio, filtered and subjected to vacuum defoaming to obtain grouting PMMA slurry; the PMMA slurry is poured into a character shell, and the character shell is subjected to exhausting and sealing, put into a continuous air and water combined heating/cooling system for polymerization, subjected to high-temperature treatment and demolding and trimming to obtain an acrylic luminous character; and finally, an LED light source is mounted in the character shell where the acrylic luminous character is embedded to obtain the LED acrylic luminous character. The preparation method can avoid acrylic leftover material problems in traditional LED acrylic luminous character manufacturing processes and light leakage and edge displaying problems in the using process and is a preparation method which is simple in process, saves materials and is small in equipment investment, feasible in engineering application and particularly suitable for the LED acrylic luminous character with complex strokes.