Abstract: Economic development necessarily requires changes to be made in highway planningand the means of surveying and designing in highway building. To speed up the designingprocess in highway construction, one mainly depends upon automation, in which thedigitization of terrain information (or DTM) is an indispensable part. This paperestablished a DTM which has taken highway designing and the characterstics of a linearproject into consideration in terms of sampling and data processing. It gives a man-machine interactive designing profile and programmes for computing the cubic meters ofearthwork and stonework of different geological structures and for drawing profiles,plans, the cross sections of specific piles, and perspective graphs of any length. At theend of the paper, experimental data have been given to show the correctness of theprogrammes. There results indicate that the application of DTM in highway designingis not only feasible but has great potentiality.