The volume expanded 6.4 percent year on year, according to the People's Bank of China (PBOC).
In breakdown, the combined assets of banking institutions came in at 268.24 trillion yuan, up 6.3 percent.
Securities institutions recorded 6.95 trillion yuan in total assets by the end of last year, up 1.7 percent year on year.
Insurance institutions saw their assets expand 9.4 percent to 18.33 trillion yuan.
Liabilities of China's financial institutions rose 6 percent year on year to 267.7 trillion yuan by the end of 2018, PBOC data showed.