The invention discloses a method for establishing a photogrammetric grassland coverage measurement map library and a use method. The map library establishing method comprises the following steps of: searching various typical types of grassland photos and representing the grassland type of each photo; sequentially listing photographing positions, shooting dates, photographing weather conditions, light supplement and the like into a grassland photo statistical table; generating a column number N1 according to the resolution N1 * N2 of each typical grassland photo; overlapping the table and the grassland photo together by a table with the line number of N2, artificially identifying the image types of the positions, corresponding to n random points generated in the table, on the grassland photo, and counting the proportion of the random points representing the grassland in all the random points, namely the real coverage of the grassland in the image; When in use, acquiring an evaluation result by comparing with a result obtained by a to-be-tested technology; The establishment method and the use method of the metering gallery are simple and easy to implement, and a platform beneficial to competition between technologies under the completely same condition is provided.