Water spraying work to prevent the dust from scattering during building dismantling operation has usually been done manually. Since it is very risky and often causes fatal accidents due to unexpected collapse, a few countries have adopted mechanical water spaying machines. However, these machines are still operated by human laborer, specifically in orienting the spraying direction, which induces low dust suppression efficiency. In this research, an automated fine dust tracking system was suggested to identify and track the dust generating position accurately. A GPS is installed on the secured body of the excavator which contains a crusher as an end-effector for building dismantlement. Assuming the position of the crusher is the dust generating spot, a forward kinematics analysis is performed to identify the crusher position from the body origin on which the GPS sensor is placed. With another GPS on the water-spraying robot, its relative position to the dust generating spot and its heading angle for tracking can be calculated consequently. Tracking experiments were conducted with a miniature excavator and a reduced size water spraying robot. The results showed a sufficient tracking performance enough to be applied to the water spaying machines.