but generally the world economic is not so bad, not like Great Depression 。 in a situation of economic depression, wars are more easier to break out

I am not sure that economic depression does make war more likely.

Yes some wars, like the French Revolutionary Wars, sprang out of poor economic conditions that in part drove social change.

However, the beginning of the 20th century was a period of huge economic growth. It was the rapid growth of the German economic and industrial power, and reactions to it, that were major causes of the first world war. It was the political legacy from WW1, more than the great depression, that led to WW2 in Europe. It was the massive military and industrial expansion of Japan in the 1920s and 30s that led to WW2 in the Pacific.

@tiger
Not sure this is true, but someone told me Japan's war, although probably inevitable, was strongly related to the US foreign policy of containment of Japan at the time.

It's been a while since we chatted, so I forgot the details - but it sounded plausible, based on the US cold war strategies and the current activities to "contain" China.

Has anyone else ever heard of this theory, allegedly based on history?

I also vaguely recall that Germany rose to power partially because of crippling restrictions against the country following WW1, which rather sounds like what's happening in Greece - although it appears Greece put itself into the stew.

Key point related to the OP, it was not related to economic depression.

Agree it was related to containment. I did use the term expansionism in my post above. Containment follows expansionism not the other way around.

Why was Japan exercising expansionism? It had become wealthy and powerful and was exercising its new military strength to get the resources (mostly oil for the rapidly growing navy that was burning 200 tons of it a day), and its industrial needs.

But whatever, it was not a result of the depression.