In order to study the mechanisms and crack’s extension law of rock like material with multi-crack under uniaxial compression, by the means of pre-burying iron sheet, the rock like material specimen with different crack stripes and angle were obtained；By using the RYL-600 shear rheometer, the specimen were loaded by the way of load control, and the process of crack initiation, extension and transfixion were recorded. The experimental results of specimen with 60°×18 stripes were analyzed in detail, the curve of axial stress- axial displacement shows that it presents three obvious stress drop stages, combined with the video of experiment process, which are divided into three stages. Moreover, the numerical simulation for specimen with 60°×18 stripes was conducted by using FLAC3D, the curve of axial stress- axial displacement and the section of failure model were obtained, the failure mode of numerical simulation experiment was analyzed, compared with the results of physic experiment, it suggested that two results agree well with each other.