Combustible vapor explosion characteristic test device (NEU-G-EL) was set up to study the explosion characteristics of nitro-thinner under the conditions of different pressure and temperature. The experimental results showed: The L-LEL (Lower Limit of Explosion) of vapor explosion of nitro-thinner was between 1.0% and 2.0%, while the L-UEL (Upper Limit of Explosion) was between 4.5% and 10.0%, and the Delta L (Range of Explosion Limit) was between 3.5% and 8.0%. The L-LEL, L-UEL, Delta L and the (Delta P)(max) (maximum over-pressure) will increase with the increase of the initial pressure, and the (Delta P)(max) of Nitro-thinner vapor explosion will decrease with the increase of the initial temperature.