The figure was up from 1.22 trillion yuan the previous month, but was down by 232.7 billion yuan from a year ago, according to the People's Bank of China.
The M2, a broad measure of money supply that covers cash in circulation and all deposits, increased 8.3 percent year on year to 234.28 trillion yuan at the end of September, the data showed.
The growth rate was 0.1 percentage points higher than the figure seen at the end of August and 2.6 percentage points lower than that seen during the same period last year.
The M1, which covers cash in circulation plus demand deposits, stood at 62.46 trillion yuan at the end of last month, up 3.7 percent year on year.
The M0, the amount of cash in circulation, increased 5.5 percent from a year ago to 8.69 trillion yuan at the end of September.
In the first three quarters, the central bank injected a total of 255.2 billion yuan of net cash into the market.
Newly added social financing, a measurement of funds that individuals and non-financial firms receive from the financial system, came in at 24.75 trillion yuan during the period, representing a 4.87-trillion-yuan drop from the same period last year and a 4.14-trillion-yuan rise from the 2019 level.
By the end of last month, total outstanding yuan deposits stood at 229.18 trillion yuan, up 8.6 percent year on year.
In the first three quarters, RMB settlements for cross-border trade amounted to 5.73 trillion yuan.
China's central bank has pledged to make its prudent monetary policy more targeted and flexible to better adapt to the needs of high-quality development and place more focus on the efficiency of financial services to support the real economy.