Abstract：According to the cube root scaling law，the test data of free-field stress(scale distance in 350 m/kt1/3)and ground motion(scale distance in 30 km/kt1/3) of a series of confined chemical explosion with spherical charges of 50，100，800，1 000，2 000 kgTNT in limestone have been analyzed，the attenuation of the free-field peak stress and the ground surface peak particle velocity，peak scaled particle displacement and peak scaled particle acceleration with scale distance are fitted，all the characteristic parameters are compared with that of nuclear explosion in hard rocks(granite，sandstone，limestone). The results show that，the ground surface peak scaled particle acceleration is far low in chemical explosions，and the others are principally in agreement with that of underground nuclear explosions. Some problems about in-situ measurements and data analysis are discussed，that mechanics effects of underground nuclear explosion could be to a certain extent simulated with underground chemical explosion is emphasized，and that a large number of on site data should be fitted statistically and it would be helpful in understanding the objective laws is also indicated. The instruments with higher frequency response must be provided in measuring free-field stress on underground chemical explosion. The higher frequency wave is attenuated quickly while propagating in rock mass，there are not distinct differences between ground motion frequencies of chemical explosion and nuclear explosion beyond a certain scale distance，acceleration is more sensitive to rock property on the travel path especially，which is the reason why the measured ground surface peak scaled particle acceleration is far low in chemical explosions.
