The invention discloses an I-shaped self-preheating burner with a grading function. The I-shaped self-preheating burner with the grading function is characterized in that a heat exchange cylinder sleeves an inner
pipe; spray holes are distributed at the head end of the heat exchange cylinder; the
tail end of the heat exchange cylinder is opened; the head end of the inner
pipe is hermetically connected to the inner side of the head end of the heat exchange cylinder; the
tail end of the inner
pipe is closed; a grading ring slidably sleeves the inner pipe; the head end of the grading ring is located in an annular space between the
tail end of the heat exchange cylinder and the inner pipe; an operating component at the tail end of the grading ring hermetically extends out of a shell; a
combustion chamber is located in the head end of the inner pipe and hermetically penetrates out of the heat exchange cylinder; a central pipe hermetically penetrates into the inner pipe and extends to the head end of the
combustion chamber; a grading pipe sleeves the central pipe; the head end of the grading pipe extends into the
combustion chamber; the tail end of the grading pipe is hermetically mounted on the shell; an ignition
electrode hermetically penetrates through the shell and extends into the inner pipe to enter the
combustion chamber; a
coal gas inlet, an air inlet and a
smoke outlet are formed in the shell; the
coal gas inlet communicates to an annular space between the tail end of the grading pipe and the central pipe; and a communication hole is formed in the side face near the tailend of the inner pipe. According to the burner, grading combustion in a high-temperature mode and a low-temperature mode is achieved, and
NOx generation is reduced.