The precision agriculture decision-making needs of geographic information visualization analysis for farmland. In order to get 3D visualization of farmland, the Matlab software and wavelet transform were used for 3D-terrain survey data processing. Haar, DB6, Sym8, coif3 wavelet were used on the 3 layer decomposition of elevation data de-noising test, DB6 wavelet was used on the two to seven layer decomposition de-noising. The measurement plane scatter plots, contour map, 3D surface chart of the farmland was drew. The research shows that using a db6 wavelet five level decomposition de-noising for elevation data measured by DGPS continuously was suitable for the 3D-terrain farmland surveying and mapping in which farmland have the more moderate wavy. This may well reflect the farmland terrain features.