Abstract: The main tectonic events and climatic changes which occurred in the last 3Ma coincide with the Earth's orbital eccentricity changes having a period of about 0.4Ma. The boundaries of tectonoclimatic cycles determined from the stratigraphic records in the Loess Plateau giving solar calendar ages of 0.07, 0.46, 0.83, 1.32, 1.70, 2.08, 2.47MaBP respectively correspond to the time intervals where there is a decrease of the eccentricity of the Earth's orbit. Also,the basic data concerning the change of speed in the Earth's revolution and its possible effects on the Earth's rotation and on the interaction between the individual geospheres have been analysed. That the changes of eccentricity of the Earth's orbit may have resulted in a driving force for tectonic movemants is discussed. Finally, it is also pointed out that a study of the tectonoclimatic cycles is of importance for further development of the geomechanics theory.