Abstract: A baluster structure of handrail includes a steel-bar threaded central post, which is circumferentially enclosed by a plastic jacket and a plastic decorative portion. The steel-bar threaded central post has top and bottom respectively forming first and second joint sections. The second joint section is mounted to a stairway and the first joint section is mounted to an underside of the handrail to form a baluster. The threads of the upper and lower sections and the thread-free middle section of the steel-bar threaded central post are enclosed by the integrally formed plastic jacket and plastic decorative portion, whereby the plastic jacket and the plastic decorative portion are rotatably fixed. The baluster is mounted to the stairway to support a handrail. The baluster is of greater strength, does not deform and bend, is safe and corrosion resistant, has an extended life span, and is environmentally conservative.