A dozing system for a bulldozer with which dozing can be carried out by a simple operation without giving a great deal of fatigue to the operator.When the running slip of a vehicle body is not detected by a running slip detector, a blade is lifted or lowered by a comparison controller such that an actual tractive force of the vehicle body detected by an actual tractive force detector becomes coincident with a target tractive force set by e.g., a dial, whereby the amount of loads applied to the blade by excavating and moving earth can be maintained constant. On the other hand, when the running slip of the vehicle body is detected by the running slip detector, the comparison controller lifts the blade, thereby reducing the amount of loads applied to the blade by excavating and moving earth in order to eliminate the running slip.