Nama Depression in 2007 and 1930 are not comparable, chief economist of the international monetary Fund (IMF) said the world risked falling into a new great depression. Although there are similarities between this crisis and that of the 1930s, much else including technology, geopolitics, and role of the state has changed dramatically in the intervening period. Whereas exotic derivatives like CDOs and CDSs only widely used in the 1990s, and europe was dominated by the treaty of versailles rather than the european union. But in recent decades many traditional views about the causes of the depression have been inverted by academics. Due the rise of protectionism, Paul Bairoch aid the depression between 1913 and 1927 rising from 24,6 % to 24,9% in those fourteen years in the europe. Although the rise of protectionism in 1930,american exports only accounted for 7% of GDP,so that only explain part of the 29.5 reduction in real GDP it between 1929 and 1933. The wall street crash caused the depression has also out in recent years by the harvard economist J.K Galbraith, who in the 1950s emphasised the importance of the stock market crash in sparking of the great depression. other than that, historians pointed out that the global economy was already on a downward path before stock prices in New York started falling. credit crunch by the start of 1929 which experienced by Europeans and Americans as with the rise of protectionism, it seems that the Wall street crash was a symptom of problems in the global economy. Economic historians such as Eichengreen and Peter Temin now focus on stressed the importance of the malfunctioning of the gold standard currency system as the cause of the depression the world financial system before 1929 and sudden economic collapse of the 1930s. in the mid-19th century a fixed value of gold came into effect in many major countries. when the achieve global economy peak they were forced to use fiscal and monetary means to reduce the economy to protect the value of fixed currency. in response to gold outflows Federal Reserve monetary policy tightening to overcome the four waves during the 1930-1933 banking crisis that bankrupt. To avoid monetary tightening, the central bank in the UK and America they cut interest rates and the use of unconventional monetary stimulus. Europe should learn from the great depressions and also must establish the euro zone. Contribution of economic historians should ensure that the past is not misused in the debate that led to the economic crisis blame on Wall Street.