The discrimination between nuclear explosions and earthquakes is an important issue for the
verification of compliance with a Comprehensive Test Ban Treaty (CTBT). Several diagnostic techniques are examined
for identifying earthquakes as events distinct from possible underground nuclear explosions such as complexity and
spectral ratio. China is a tectonically and seismically complicated region, especially in the western part. Seismicity is
active in North China. The objective of this paper is discriminating the nuclear explosions from natural earthquakes in
China region by using the complexity and spectral ratio tools for a set of seven nuclear explosions and seven
earthquakes with 4.5 ≤ mb ≤ 6.5. It was found that, the complexity of natural events (earthquakes) is higher than of
artificial events (explosions), therefore, natural earthquakes are more complex than nuclear explosions at teleseismic
distances and separation is clear between both of them. On the other hand, the spectral ratio is larger for explosions
than for earthquakes due to the seismogram of explosions have higher frequency content than that for earthquakes.