The invention belongs to the technical field of measurement and calculation, and relates to a method for measuring and calculating the regulation scale of an artificial fish shelter, aiming at solving the problem that the existing method for measuring and calculating the regulation scale of the artificial fish shelter flow field can not meet the requirements of measurement and calculation. The invention provides a measuring and calculating method which comprises the steps of: carrying out three-dimensional shaping on an artificial fish shelter by computer aided design, arranging a fish shelter monomer or a multi-fish shelter complex into a numerical flume, conducting three-dimensional grid subdivision on the numerical flume, importing grid data into a common CFD software, selecting a large-eddy simulation on turbulence modeling, numerically simulating the flow field change of the fish shelter after putting, and analyzing the output calculation results, thus being capable of obtaining the differences of characteristic dimension of flow fields such a slow flow area, an upward flow area and the like under different types of conditions of fish shelters, water depth, shelter combinations and the like. The method is used for measuring and calculating the flow field regulation scales of different types of shelter bodies and shelter body combination under different water depths and flow velocities, and provides scientific data for optimization and configuration of the fish shelter monomer design and the multi-shelter combination scheme.