Abstract: As an advanced type of taxi appears in everyday life,the chauffeured car service provides a service similar to the dial-a-ride service.In order to improve the quality of chauffeured car service,it is necessary to investigate the de-mand of the chauffeured cars in a city.This paper assumes that the total number of taxis in a city is composed of the regu-lar taxis and extended chauffeured cars.The number of chauffeured cars and regular taxis is allocated according to the or-dinal utility theory in economics,and thus the demand of chauffeured car service in a city is determined.The numerous example analyses indicate the proposed method is feasible.This method not only expands the method of determining the quantity of taxis required in a city,but also provides a tool for the planning and design of operation routes,real-time scheduling and dispatching for.