As the terrain generation algorithm has trouble balancing ease of use, controllability, realism, and speed, this study proposes a terrain generation method based on sketch maps. This method uses the generative adversarial network to model the terrain slope, slope aspect, and other information in the hidden space so that the generated terrain conforms to the constraints of the user’s hand-drawn sketch map. This study also proposes a sketch map extraction algorithm based on terrain height maps, and it can extract a sketch map to a hand-drawn effect from a real terrain height map and quickly build the data set. An algorithm for multi-scale terrain detail filling is proposed. Owing to the introduction of the multi-scale concept, the terrain texture details are dynamically supplemented, and the realism and aesthetic properties are greatly improved. A terrain satisfaction evaluation method based on user feedback is proposed and verified by experiments. The results show that the proposed terrain generation method can accurately and efficiently generate digital terrain that meets users’ expectations.