"I always be with you"这句话有语法错误吗？

有语法错误。be动词搭配错误。

改正：I'm always with you. 现在一般时，两层表义：我总是支持你。或我总是陪伴在你左右。

亦可使用过去一般时，如：I was always with you, but you made me disappointed again and again.