The invention relates to a geology evaluation method for an offshore sedimentary rock oil field. The geology evaluation method for the offshore sedimentary rock oil field comprises the following steps of: manufacturing a geology analog map; marking each geological parameter of a target oil field onto the geology analog map to obtain a plurality of target oil field mark points; successively connecting the target oil field mark points along each stage coordinate axis in order to obtain a target oil field polygon; selecting oil fields to be subjected to analogy with the target oil field; respectively marking each geological parameter of each oil field to be subjected to analogy to obtain a plurality of oil field mark points to be subjected to analogy; successively connecting the oil field mark points along each stage coordinate axis in order to obtain a polygon of the oil field to be subjected to analogy, and so forth, obtaining the polygons of all the oil fields to be subjected to analogy; carrying out analogy to the shape of the polygon of each oil field to be subjected to analogy with the shape of the target oil field polygon, and preliminarily determining the oil fields with the similar characteristic with the target oil field; carrying out secondary screening to each oil field to be subjected to analogy, which is obtained by original selection, so as to obtain the oil field to be subjected to analogy, which has the highest level of similarity with the oil field geology characteristic; and according to the obtained oil field to be subjected to analogy, guiding the target oil field to formulate a development strategy. The geology evaluation method for the offshore sedimentary rock oil field, which is disclosed by the invention, can be widely applied to the geology evaluation of the offshore sedimentary rock oil field and the oil field development.