CV. Trans Langgeng is a car rental company located in Kaliurang street Km 13 – Yogyakarta. It provides car rental service. The cars are distinguished from one another based on the type, price, and facilities of the car. Customers can make order booking of the rental cars over the phone or complete the Transaction directly at the rental. In promoting the company, it raises customers' awareness of the service by customers' spreading the information to others. However, it eventually gave inadequate effectivity because the company could not present information about the rental cars in detail completely. It resulted in customers' lack of information about the rental cars of CV. Trans Langgeng. To solve the existing problem, a promoting system application was created. In addition, a website-based online booking was also established at CV. Trans Langgeng. And creat with php language program, and MySQL database, yii framework, and testing in web browser. Based on the result of the research and black-box testing on WEB-BASED MANAGEMENT INFORMATION SYSTEM at CV. TRANS LANGGENG, the website has helped improve the car rental service and promote the rental cars to customers at CV. Trans Langgeng.