At the Congress of the SPD in Berlin, he denounced the eurosceptics and the "racist" rhetoric of President Donald trump.
The Congress unanimously supported Schulz as the candidate of the party, who will lead her before the election in September.
Since 2013 SPD is included in the ruling "Grand coalition" as a Junior partner.
The party hopes that Schultz, a former President of the European Parliament, will lead it to victory in the elections to the Bundestag and the parliamentary majority that will allow it to form a government without entering into a coalition with the Christian democratic Union.
So far, the exit polls indicate that the social Democrats are lagging behind the CDU, although personal electoral ratings Schultz is approximately equal to the ratings of Merkel, who is going for the fourth time to run for election.
Speaking at the party Congress on Sunday, Martin Schulz blamed for the rise of populist sentiments on the growing income gap between the middle working class and wealthy sectors of society.
61-year-old politician criticized the Board of the Christian Democrats to lower taxes and increase defense spending at the expense of social programs.
Schultz also stated that in his post of the head of the European Parliament, he has always been opposed by those who are "trying to destroy the European unity".
"These people consider me their resolute opponent," he said.
He also condemned the statements of Donald trump, calling them misogynistic, anti-democratic and racist.
Martin Schulz was the only candidate for the post of party Chairman. He got 100% of votes of deputies of the Congress - that has not happened since the second world war the social Democrats.
He will replace on this post of Sigmar Gabriel, who in January resigned, hoping to improve the chances of the party to win the election.
Schultz in the past engaged in bookselling. He is a native of Aachen on the Dutch border and once wanted to become a professional footballer.