In order to analyze the lane-changing behavior on the upstream of the intersections, based on the cellular automata traffic theory, a comprehensive lane-changing model for the traffic flow near the approach is proposed by combining the improved mandatory lane-changing model and discretionary lane-changing model. And the charts describing the scenarios of the space-time and traffic density for the traffic flow near the approach are obtained through simulation based on the comprehensive lane-changing model. Results show that the lane-changing rate at the approach is higher when the traffic density is in the ranges of [0, 0.2] and [0.4, 0.6]. The average vehicle speed is gradually reduced as lane-changing rate increases under median low vehicle stream density, but the variation of vehicle speed with lane-changing rate is not significant under high vehicle stream density.