The flag used by the Mengjiang United Autonomous Government consists of a horizontal colour pattern of yellow, blue, white, red, white, blue and again yellow.

Mengjiang

Flag of the Mengjiang United Autonomous Government
Use	National flag
Proportion	2:3
Adopted	1 September 1939
Design	A horizontal red bar in the middle, with two thin white bars surrounding it, within a blue bar, on a yellow field.

The colors on the flag were used to represent major ethnic groups in Mengjiang: blue for the Mongols; red for the Japanese; yellow for the Han and white for the "Hui" (the name given to the Muslims at that time).^[1]

South Chahar, North Shanxi and the Mongol Military Government each had their respective flags before merged with the Mengjiang United Autonomous Government.

• 
  Flag of the Mongol Military Government (1936-1937)
• 
  Flag of the Mongol United Autonomous Government (1937-1939)
• 
  Flag of the South Chahar Autonomous Government (1938-1939)
• 
  Flag of the North Shanxi Autonomous Government (1938-1939)^[2]

The colors on the flag of Mengjiang is similar to the Five Races Under One Union flag formerly used by the Republic of China.