Gasification furnace

A gasification furnace is disclosed. The gasification furnace comprises: an outer housing (100) with an inlet and an outlet on the top and bottom respectively; an inner housing (200), which is composed of a membrane wall having an cooling water inlet (N2) and an cooling water outlet (N3) and is arranged in and spaced away from the outer housing (100), thereby defining a gasification chamber; a nozzle (1); a lower housing (300) which defines a slag exhausting chamber connected with the gasification chamber, and is arranged with a slag exhausting port (7) at the bottom and an gas discharging port (N5) on the top lateral wall; a cooler (9) which surrounds the outer housing outlet and is connected to the outer bottom wall of the outer housing (100); a positioning element (11) arranged between the inner bottom wall of the outer housing (100) and the inner housing (200); and a gas guiding pipeline (10) with its top end connected with the cooler (9) and the bottom end extending downward in the slag exhausting chamber. The gasification furnace can utilize high ash fusion temperature coal as raw material to generate gas, has high scour resistance capability and is convenient for replacement.