The invention discloses a method for constructing a graded crushed rock micro-mechanical model and calibrating a micro-mechanical parameter. The graded crushed rock micro-mechanical model is constructed through a test on a graded crushed rock basic parameter, simulation of a test mold and generation of the simulation test piece by endowing the micro-mechanical parameter to a simulation test piece; a micro-mechanical model test piece is subjected to a value experiment, so that a graded crushed rock stress strain curve is obtained through stimulation; and the micro-mechanical parameter of the graded crushed rock micro-mechanical model can be calibrated by analyzing the comparison between an actual test result and a simulation structure of graded crushed rock stress strain according to a simulation error precision requirement. By the method, the graded crushed rock micro-mechanical model can be constructed accurately and quickly and the micro-mechanical parameter can be calibrated, so that an effective tool is provided for deep research on a mechanical behavior and a damage mechanism of graded crushed rocks.