After entering the customs, nomadic people were very cruel and killed many civilians in the war. Therefore, the people have great resistance to the Jin people and are unwilling to submit, which will be very unfavorable to the rule of the Jin people. As a result, Huang Taiji succeeded to the throne for ten years and changed "Daikin" to "Daqing". Although this has not changed in essence, it will feel better psychologically for the persecuted people, and it will not feel like submission to Daikin, and it will also help to dilute people's hatred for Jin people.
There is also a saying that from the perspective of geomantic omen, Daikin happens to be the gold in the five elements, and the "sun" on the left side of the Ming Dynasty happens to be fire, which means gold, so the name of the country should be changed. On the left of the word "Qing" is water, which means "fire" and has similar pronunciation. Therefore, Huang Taiji changed "Dajin" to "Daqing". Not only that, but also changed the Jurchen nationality into Manchu nationality, all of which used "water".
In addition, it was Yuan Chonghuan who led troops to fight against the Qing army in the Ming Dynasty. Huang taiji thought that this kind of "fire" was not conducive to the victory of the war, so he made up his mind to change it to "Qing" Later, after the victory of the Anti-Japanese War, Wu Sangui defected and the Qing army entered the customs. Huang Taiji believed that it was because the country name was changed. Therefore, the country name has always been "Qing" and has never changed.