Well over 100 B-25Cs and Ds were supplied to the Nationalist Chinese during the Second World War. In addition, a total of 131 B-25Js were supplied to China under Lend-Lease.
Following the end of the war in the Pacific, four bombardment squadrons (the 1st, 2nd, 3rd, and 4th) of the 1st Medium Bomber Group were established to fight against the Communist insurgency that was rapidly spreading throughout the country. During the civil war, Chinese Mitchells fought alongside DeHavilland Mosquitos.
In December 1948, the Nationalists were forced to move to the island of Taiwan, taking many of their Mitchells with them. However, some B-25s were left behind and were impressed into service with the air force of the new People's Republic of China. However, I don't know if any Chinese B-25s participated in the Korean War.
43-3870/4104 North American B-25J-1 Mitchell 3894 to Chinese Nationalist Air Force 3896 to Chinese Nationalist Air Force 3987 to Chinese Nationalist Air Force 43-4105/4404 North American B-25H-1 Mitchell 4113 to Chinese Nationalist Air Force 4114 to Chinese Nationalist Air Force 4116 to Chinese Nationalist Air Force 4124 to Chinese Nationalist Air Force 4146 to Chinese Nationalist Air Force 4183 to Chinese Nationalist Air Force 4184 to Chinese Nationalist Air Force 4186 to Chinese Nationalist Air Force 4188 to Chinese Nationalist Air Force 4189 to Chinese Nationalist Air Force 4193 to Chinese Nationalist Air Force 4199 to Chinese Nationalist Air Force 4201 to Chinese Nationalist Air Force 43-4405/4704 North American B-25H-5 Mitchell 4478 to Chinese Nationalist Air Force 4481 to Chinese Nationalist Air Force 4483 to Chinese Nationalist Air Force 4587 to Chinese Nationalist Air Force 4588 to Chinese Nationalist Air Force 4589 to Chinese Nationalist Air Force 4590 to Chinese Nationalist Air Force 4662 to Chinese Nationalist Air Force 4663 to Chinese Nationalist Air Force 4668 to Chinese Nationalist Air Force 4674 to Chinese Nationalist Air Force 4678 to Chinese Nationalist Air Force 4679 to Chinese Nationalist Air Force 4680 to Chinese Nationalist Air Force 4681 to Chinese Nationalist Air Force 44-30911/31510 North American B-25J-30/32 Mitchell 31387 to Chinese Nationalist Air Force 31388 to Chinese Nationalist Air Force
This list is obviously incomplete, and I would appreciate hearing from anyone who has any additions or corrections.