The present application discloses a method and system for determining a three-dimensional digital outcrop geologic model. The method comprises the following steps that: the terrain characteristic information of a target outcrop is acquired, the target outcrop is divided into at least one upright area outcrop, at least one horizontal area outcrop and a ground surface shallow-layer outcrop; the geological information of the target outcrop is determined; the spatial positioning data of the upright area outcrops, the spatial positioning data of the horizontal area outcrops and the spatial positioning data of the ground surface shallow-layer outcrops are determined; the three-dimensional data body of the upright area outcrops, the three-dimensional data body of the horizontal area outcrops, and the three-dimensional data body of the ground surface shallow-layer outcrops are determined; and the three-dimensional digital outcrop geologic model of the target outcrop is determined based on the geological information of the target outcrop, the three-dimensional data body of the upright area outcrops, the three-dimensional data body of the horizontal area outcrops and the three-dimensional data body of the ground surface shallow-layer outcrops. With the method and system adopted, the reliability of the determination of the three-dimensional digital outcrop geologic model can be improved.