Abstract: The feasibility of normalization with multi-external standards using relative sensitivity coefficients was discussed. 43 major, minor and trace elements in natural garnet samples were determined with this calibration method. The results were in well agreement with those obtained by internal calibration. The variation of relative sensitivity coefficients by ablation sampling with laser linear scanning and spot ablation was investigated. The results indicate that there is no remarkable difference for the relative sensitivity coefficients by different ablation sampling modes of laser linear scanning and spot ablation when ablating depth is same.