The attenuation regularity of detonator output shock pressure in PMMA was studied with piezoresistive manganin gauges. Good linear relationship of lnp-x was obtained by fitting experimental data (x，lnp) with least square method. The attenuation coefficient of detonator output shock pressure was also compared to the similar data reported in literatures. The results show that the attenuation coefficient is related to the diameter and height of charge obtained above. The absolute value of attenuation coefficient increases with decreasing the diameter and height of charge. The obtained attenuation coefficient of detonator output waveform in PMMA is -0.3587.