Abstract: Based on practical examples,the paper describes the theory of similarity law used for simulation of underground deep hole blasting and the way to obtain practical blasting parameters based on results of blasting experiment using simulation model.It is impossible to make every influencing factor meet the similarity low.But it is possible to identify the influencing extent of each factor and to make the main factors meet the similarity law while the unimportant factors are ignored.The manufacturing of small-scale cement-mortar model for experiment is also introduced.