The Type 61 (B) was an upgraded production variant of the original Type 61, and from 1966 onward it became the de facto standard Type 61. The upgrade introduced several practical improvements, including revised fuel stowage and relocated external tools. Some Type 61 (B) tanks were also fitted with the Type 69 night-vision sight and visible/IR floodlights, primarily for night operations units within tank battalions. The Type 61 remained in service until 2000, when it was finally completely replaced by the Type 74 MBT and the roll-in phase of the Type 90 MBT.

The Type 61 (B) was introduced in Update 2.53 "Line of Contact". It looks like a bizarre cross between the American M41 Walker Bulldog and the Patton series (M46/47/48). It is very similar in overall length and size to the M41, and the turret looks like that of the M60, with the same prominent commander’s cupola on top of the turret housing a rangefinder. The Type 61 mimics the American M47 Patton in firepower and the M41 Walker Bulldog in armour; it has the large, tall profile and fairly mobile medium tank characteristics of the M47 Patton, with the same decent 90 mm M36 (Type 61) cannon, but the armour protection qualities are more akin to those of the M41.