In this paper, driving data distribution of human drivers in urban driving condition are presented by using China-FOT data. Longitudinal acceleration, lateral acceleration and longitudinal velocity are the three vehicle dynamic parameters which are concerned in the study of human driver behaviors. The data distributions of these three parameters are studied. It is found that the lateral acceleration versus longitudinal acceleration diagram shows the dual triangle distribution, and the speed based diagrams present piecewise linear distribution. Next, whether the database is sufficiently large to get steady distribution and boundary is discussed. And the data distribution boundaries of these three parameters are achieved. In the last, acceleration distribution at different speed region is presented.