Experimental research on relative quantitative evaluation is developed based on Lamb wave structural damage diagnosis technology. Based on circular single transmitter multi-receiver（ STMR） array

accuracy and effectiveness of Lamb wave-based structural damage diagnosis technology in localization recognition is verified by numerical calculation. Feasibility of diagnostic factor（ DF） taken as effective parameter of relative quantitative evaluation for structural damage is analyzed. Experimental verification is presented by presetting three different sizes of damages. Experimental results show that quantitative comparative analysis on relative severity of damage is carried out by comparing value of DF at damage position under different working condition

it has good prospects for engineering application.