Abstract: The compression of vector data is very important for reducing the space needed for data storage and improving the efficiency of data transmission and processing in WebGIS. This paper focuses on the time efficiency of vector data compression with prediction functions and proposes a vector data compression method based on sector screening that significantly reduces the quantity of candidate vertices in prediction areas to improve time efficiency. Experimental results show that the time efficiency improved by 30%-40%. Our method was compared with the conventional Douglas-Peucker method. The tests confirmed that our method can achieve a larger compression ratio when using the same compression threshold value, while obtain greater time efficiency with relatively small threshold values.