Since the warhead of an intercontinental missile is a hydrogen bomb, why is it said that only China has a hydrogen bomb in the world today?

The warhead of an intercontinental missile is not a hydrogen bomb. It is more complicated than the hydrogen bomb. There may be some misunderstanding. Generally speaking, the atomic bomb we are talking about is a fission bomb, which is realized by nuclear fission reaction after high-purity plutonium -239 or uranium -235 exceeds the critical mass. Hydrogen bombs are powered by atomic bombs, which realize the fusion of heavy hydrogen atoms and release more energy. The atomic bomb of fission reaction is generally called a first-phase bomb, and the hydrogen bomb of fusion reaction is generally called a two-phase bomb. Nowadays, the commonly used nuclear warheads are generally called three-phase bombs, which is a more complicated guy. Lighter weight, higher utilization rate and appropriate power can be used in strategic missiles. As for China's hydrogen bomb, if it does exist, it should have a thicker shield and a longer storage time. But we don't have nuclear bombers. It's useless if it can't be mounted on a strategic missile. It can't be used to dig reservoirs like the former Soviet Union.