The burst strength is one of the most important characteristics for nonwovens. The strength of three kinds of the nonwoven were detected under four testing radius, including the wood spunlace nonwoven, the Spunbond-Meltblown-Spunbond (SMS) nonwoven and the melt nonwoven. The precise results of the SMS and the melt nonwoven could be received by removing the influence of the elastic membrane and the single-peak fitting. The influence of the testing radius to the strength results was also studied, and the semiempirical formula (q0=k/r3) was deduced using the elastic mechanics theory and testing data.