Abstract: With the help of surveying robot Leica TM30, this paper calculates three-dimensional coordinates of the station sites and collects the data from the top and low layer monitoring points on the derrick based on the method of three-dimensional measurement on free station．After a rigorous adjustment, coordinates of each station site are calculated, so are the two-tier’s center coordinates of the derrick. And then the derrick inclination is calculated according to the two-tier center offset and the height difference between the two layers. The feasibility of this method has been verified by the monitoring data of the main shaft derrick in Tangkou mine．The experiments show that this method is better than the conventional one in its simple implementation and efficiency．