Abstract: Based on the mechanism analysis,the elastic plastic model of space formation caused by blasting with linear charges is established. In terms of state equation of blasting and conservation law of matter, evaluation formula based on elastic plastic analysis to estimate space diameter caused by blasting with linear charges is given. The procedure of evaluation is introduced.By comparing the results of in site experiments with calculation,the rationality of the method to evaluate the space diameter caused by blasting with linear charges is proved.