In the office, a company needs a comfortable place for employees to carry out their work activities in realizing their predetermined goal. Office layout is an absolute thing in supporting the succesfull process of a work activities. Therefore, office interior design management is important so that employees could get enough spaces to do their work, the benefits that can be obtained from office interior design is that company can increase enthusiasm and spirit of work for the employees. A good office can help employees focus more on performing tasks and work efficiency. The purpose of this research is to know the office interior design and environmental conditions of the office and provide an alternative arrangement of better office interior design. The method used is descriptive method by using both quantitative and qualitative type of data collected by conducting interview, observation and literature study.. It is found that the office layout at PT Astra International TbkIsuzu Semarang office administration is not arranged based on the theory that suggested. The office interior design type used is open office interior design type. There are several causes that make the office interior design at PT Astra International Tbk-Isuzu Semarang admin office is not good including the tidiness of office such as untidy documents, the arrangement of furniture and office equipment which is less appropriate, noisy conditions caused by the office machines and also lack of air circulation. This condition can be overcome by managing documents and utilizing the function of filling cabinet in document storage. To overcome the noise caused by a typewriter can be done by moving the position of the typewriter at the corner of the room close to the wall. Giving the glass partition to form a space which can prevent noises from outside the admin office. Temperature and humidity can be maintained with the use of Exhaust fan.