The Great Leap Forward failed primarily due to poor decision-making and lack of foresight. Beginning in 1958 and lasting until 1961, this large-scale and speedy industrialization of China resulted in one of history's worst famines and a period of economic depression.
The Great Leap Forward was spearheaded by Mao Zedong, then Chairman of the Central Committee of the People's Republic of China. Mao's policies during this time were structured to shift China from a primarily agrarian economy to an industrialized and modern one, resulting in a ban on private farming and a collectivization of agricultural goods. Part of Mao's plan for the industrialization of China was to instruct peasants to create so-called "backyard furnaces," and as a result citizens melted massive quantities of pots, pans and other household items made of steel. Mao soon discovered that the high-quality steel he was after could only be created in large factories, rendering the sacrifices of the peasants useless.
Another reason the Great Leap Forward was a colossal failure was Mao's initiative to have massive numbers of sparrows killed. Sparrows were believed to be stealing grain seeds from the people. As a result of the sparrows dying, locust swarms began to grow and eradicated a large number of crops. This in turn caused a famine that led to the death of millions of Chinese people.