The main objective of this thesis is the downward continuation of the Geopotential in Switzerland. The downward continuation of the airborne gravity data in Switzerland is a challenging task, due to the well known mountainous topography (Alps) . Another interesting factor for the analysis of the downward continuation process is the measurement height (Flight-line altitude), which is about 5000m above sea level. Taking into account these factors, it is convenient to study the downward continuation process using different computation methods as well as different techniques that take into account the topography. The Principal method proposed in this thesis for the downward continuation of Geopotential in Switzerland is the combination of the Sequential Multipole Analysis (SMA) and Least Square Collocation (LSC) with regularization in the Bjerhammar-Krarup model. This method is then compared with the inverse Poisson’s integral method. To improve the stability of the downward continuation process, a number of land (19 GPS/leveling points) data is included in the calculation. The final results from both methods are stored as geoid undulations and are compared with the actual geoid of Switzerland CHGeo98. Since the topography of Switzerland is rough in the south and relative smooth in the north, I propose to use different terrain correction techniques, the second Helmert’s condensation technique and the Residual Terrain Model (RTM) technique.