Abstract: Improving the workforce quality of foremans, skill labors and workers has an important role in improving the quality of the building. In addition to bridging communication between site engineer and site manager with workforce in the field, the field executives must have technical skills and managerial or leadership skills in direct contact with the foreman, skilled workers and hired workers. From the organizational relationship, the field execution must be able to apply the working drawings with the implementation method into the building by optimizing the available resources. The leadership and communication methods being developed must be fully understood to make no doubt the foreman, the skill labours and the workers in carrying out the series of development activities. This study aims to obtain the factors that influence the relationships of the leadership of field managers on motivation and performance improvement of workforce, i.e., foreman, skill labors and workers in the contractor company and make the modeling. The research was conducted on the contractors grade 5-7 in Malang, Surabaya, Blitar and Probolinggo. Data collection is obtained through questionnaires and interviews. The Structural Equation Model (SEM) method is used to see the relationship among variables. Then, the results are analyzed to model the relationship between leadership of field executive upon motivation and improvement of workforce performance factors. The results show the leadership of the field manager affects to the improvement of the workforce performance. While the work motivation has an effect on the workforce performance. Whereas, the leadership affects to the work motivation. And the leadership has an indirect effect on the improvement of workforce performance through motivation.