With the expansion of urban area and development of taxi system,problems arise,such as low operation efficiency,high taxi idling rate,and long passenger waiting-time. Although various studies have been conducted,only limited overview of the factors towards urban taxi system has been provided. Consequently,a comprehensive evaluation of taxi system is essential for the urban planner to analyze the current situation and take effective measures. This paper,by using Floating Car Data( FCD),proposes a Comprehensive Taxi Assessment Index( CTAI) to quantify the quality of existing urban taxi system with the assistance of Geographic Information System( GIS) technology. The proposed index system extracts and classifies key factors,reflecting the taxi system from the perspectives of operation efficiency,customer and taxi-driver satisfaction. The system contributes to improving the organization and operation of urban taxi system. Based on the data obtained from the city of Shenzhen,Guangdong Province,China,for both weekday and weekends( Dec.,2011),the proposed CTAI was illustrated by using the Principal Component Analysis( PCA) with ArcGIS 10. 0 platform. The results indicate that the system provides a good multi-dimensional view to delve into the existing urban taxi operation, thus to point out the most sensitive indices towards the entire system,which consequently provides guidelines for future improvement and management of urban taxi system. With the expansion of urban area and development of taxi system, problems arise, such as low operation efficiency, high taxi idling rate, and long passenger waiting-time. This paper, by using Floating Car Data (FCD), proposes a Comprehensive Taxi Assessment Index (CTAI) to quantify the quality of existing urban taxi system with the assistance of Geographic Information System (GIS) technology. The proposed index system extracts and classifies key factors, reflecting the taxi system from the perspectives of operation efficiency, customer and taxi-driver satisfaction. The system contributes to improving the organization and operation of urban taxi system. Based on the data obtained from the city of Shenzhen, Guangdong Provi The proposed CTAI was illustrated by using the Principal Component Analysis (PCA) with ArcGIS 10. 0 platform. The results indicating that the system provides a good multi-dimensional view (Dec., 2011) to delve into the existing urban taxi operation, thus to point out the most sensitive indices towards the entire system, which causes provides for future improvement and management of urban taxi system.