The new film is set to become an epic and is centred around the Nanjing Massacre.
It follows the historical story of the slaughter of thousands of Chinese citizens by the Japanese in 1937.
Bale will play the role of a priest called John who helps some of the those lined up to be killed escape with the help of the German businessman called John Rabe.
Speaking to The Hollywood Reporter, Zhang said: 'I met Christian in America and was impressed with his serious book research for the role.
'It's the overall strategy for Chinese cinema to approach the world and broaden its influence but casting Bale was a coincidence because the script happened to have an English-speaking part in the lead.'