The archaeological excavation is a very delicate moment, the decision to bring back to the light the remains of the past collides with the need to preserve them for the future: the operations of excavation, the rushed shift to very different thermo-hygrometric conditions from the burying, the exposure to weather and pollutants can cause much damage to the manufactures. The diagnostic investigations previously carried out and during the excavations provide important data from a point of view of safeguarding: before proceeding with the excavation, the findings can be localized with techniques such as the georadar, the thermovision, the aerial photogrammetry, the infrared video in color from above, or even with essays and wholes inspection. During the excavation phase it is essential the cataloging of the rests and the Survey of the Stratigraphic Units, to obtain a complete reconstruction of the site and its history. The relationship between objects found and the stratigraphic levels is very important for the dating, both based on artistic characters, then with methods such as carbon-14 or thermoluminescence.