If you stay in Beijing for a few months, you will want to live there for good.
请问will want 这种用法对吗?
你的句子中的 will want 没有错,因为是表示将来的想法。
如果是表示将来的情况,want完全可以用于将来时态。如:
He’s ensured that his children will want for nothing (= will have everything they need). 他得到保证他的子女将什么也不会缺少。
Imagine a doll that has your face and is your doll! Everyone will want one. 设想有这么一个布娃娃,它面孔像你、而且是你的,肯定每个人都想有一个这样的布娃娃。