The cabinet approved a budget of 52.82 billion baht on Tuesday to join the China-led Asian Infrastructure Investment Bank seen as a rival to the US-led World Bank, government spokesman Sansern Kaewkamnerd said.
Despite opposition from Washington, US allies including Australia, Britain, Germany and the Philippines have agreed to join the AIIB in recognition of China's growing economic clout.
The government will hold around 1.43% share of the bank, Maj Gen Sansern told reporters.
Payment will start with five installments, each at 2.112 billion baht, due by the end of 2019, he said.
The AIIB, launched on Jan 16 by Chinese President Xi Jinping, aims to invest in infrastructure and connectivity.