The invention relates to a site calibration method and device implementing the method. The objective of the invention is to solve a problem that it is difficult to ensure position precision of a target which is calibrated by use of a calibration method in the prior art. When the site calibration method is used for calibrating a target relative site position, a site is firstly divided into multiple local coordinate systems capable of covering the whole site, and then calculation of the specific position coordinate of a decision point can be achieved in the following three steps of step 1, solving the whole-site coordinate of the decision point through image coordinate three-dimensional reconstruction; step 2, according to the whole-site coordinate of the decision point, selecting an optimal local coordinate capable of allowing a metering result to be most precise; and step 3, solving the final whole-site coordinate of the decision points through a coordinate conversion mode. The solved final whole-site coordinate is based on the whole-site model obtained in the step 1, so the final whole-site coordinate is the result relative to the whole-site model obtained in the step 1. Thus, effects on calibration precision imposed by construction errors can be minimized.