© Avestia Publishing, 2016.The employee performance as one of the most important factors affecting productivity and quality, is influenced by working methods and the conditions of working environment. Negative conditions in working environment cause decrease on employee performance, besides unsuitable working postures resulting from these conditions increase the risk of occupational musculoskeletal disorders. In this study, wiring harness assembly line of a company that produces wiring harnesses for the automotive industry was investigated. It was observed that during the assembly processes on the conveyor line, the bending and reaching movements of the employees are frequently repeated throughout the working hours. Employees work on a conveyor line with fixed height and slope angle. The purpose of this study is to improve working conditions and to protect employee health by reducing ergonomically unsuitable working postures. Firstly, the movements of the employees working in the assembly processes were analyzed using the Anybody Modeling System. According to the results of the analysis, it was seen that the bending and reaching movements had high values in muscle activations and joint reaction forces. As a result of the evaluation, the conveyor line was redesigned to be more compatible with employees. In the new assembly system designed; the height and inclination angle of assembly table can be adjusted according to the height of the employee to eliminate the reaching, turning or bending movements. Ergonomics analysis were repeated for the new conveyor line designed and it was seen that the risky and unhealthy postures of employees have decreased.