The disclosure discloses a reformer of a device for preparing hydrogen with methanol and water and a manufacture process thereof, relating to the device for preparing hydrogen with methanol and water technical field. The reformer of the device for preparing hydrogen with methanol and water includes a reforming housing, the reforming housing includes a stainless steel internal shell, a thermal insulation layer and a mica external shell from inside to outside in sequence, a ratio of a diameter of the reforming housing to a thickness of the stainless steel internal shell is 150:0.8˜150:2.5, a ratio of the diameter of the reforming housing to a thickness of the thermal insulation layer is 150:10˜150:20, a ratio of the diameter of the reforming housing to a thickness of the mica external shell is 150:1.5˜150:3.5. Advantages of the disclosure include thermal preservation, high strength, corrosion resistance, lightweight, etc.