In order to reveal rocks' deformation law under long-time load, similar rock specimens' creep constitutive was studied with a comprehensive method of theoretical analysis, test and numerical simulation. Samples' conventional tests were done with WAW-32000 testing machine and indoor long-time creep tests were done with RLJW-2000 testing machine. Results show that, similar rock specimens' uniaxial compressive strength is 2.65 MPa; when stress is lower than its failure threshold 4.792 KN, specimens appear only two stages of initial creep and steady-state creep; when stress is higher than the threshold, specimens appear accelerated creep stage. According to the test and equivalent coordination deformation principle, nonlinear CYJ creep constitutive is derived and nested into FLAC 3D , model's solution agrees well with the test results.