NOVELTY - A fluidized bed reactor comprises fluidized bed (1) provided with gas inlet. Gas inlet is provided at the upper part gas distributor (3). Fluidized bed is provided at upper part of horizontal air distributing plate (4). Fluidized bed is divided into two sections or more than two sections in axial direction, to form two or more than two catalyst dense phase reaction section (5). Fluidized bed inside or outside is provided with cylinder wall of fluidized bed of the overflow pipe (6). Overflow pipe is connected with fluidized bed catalyst dense phase reaction section.    USE - Fluidized bed reactor for producing methanol from synthetic natural gas (claimed).    ADVANTAGE - The reactor has good performance. It can allow hydrogen/carbon dioxide (H2/CO) to operate and improve thickness of the reactor methanol outlet; reduces quantity of recycle hydrogen; and has low energy consumption, has reactor section for large flux, and has large operation flexibility. The reactor also has high CO conversion rate, and low production cost.    DETAILED DESCRIPTION - Fluidized bed reactor comprises fluidized bed (1) provided with gas inlet. Gas inlet is provided at the upper part gas distributor (3). Fluidized bed is provided at upper part of one or more holes with horizontal air distributing plate (4). Fluidized bed is divided into two sections or more than two sections in axial direction, to form two or more than two catalyst dense phase reaction section (5). Fluidized bed inside or outside is provided with one or more than one connected with cylinder wall of fluidized bed of the overflow pipe (6). Overflow pipe is connected with fluidized bed catalyst dense phase reaction section. Fluidized bed above the cylinder wall is provided with catalyst inlet. Fluidized bed is cylinder wall provided with number of inactive catalyst outlet. Fluidized bed is connected with cylinder wall of fluidized bed of gas-solid separating device. Catalyst dense phase reaction section is provided with eat exchange pipe. Fluidized bed is connected with gas-solid separating device air outlet. An INDEPENDENT CLAIM is included for producing methanol from synthetic natural gas which comprises putting catalyst into fluidized bed, introducing hydrogen, and introducing synthetic gas into fluidized bed gas inlet.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram illustrating a fluidized bed reactor.    Fluidized bed (1)    Gas distributor (3)    Horizontal air distributing plate (4)    Catalyst dense phase reaction section (5)    Overflow pipe (6)