After the First World War and the Wall Street crash, Germany's economy was at an all time low point. The recession had increased the number of the unemployed significantly and morale was low.
The Nazi party promised jobs and the protection of workers as well as the suspension of trade unions - appealing to workers and the larger industrialists. They also offered protection from communism, which was a looming threat at the time, as well as a promise that they would create a strong government and economy.
The ability of the Nazis to blame all of Germany's problems on the Jews and other undesirables also appealed to the voters as they trusted the Nazis to solve this issue and overcome the embarrassment of the Treaty of Versailles.