A method for Fischer-Tropsch synthesis, the method including: 1) gasifying a raw material to obtain a crude syngas including H2, CO and CO2; 2) electrolyzing a saturated NaCl solution using a chloralkali process to obtain a NaOH solution, H2 and H2; 3) removing the CO2 in the crude syngas using the NaOH solution obtained in 2) to obtain a pure syngas; and 4) insufflating the H2 obtained in 2) to the pure syngas to adjust a mole ratio of CO/H2 in the pure syngas, and then introducing the pure syngas for Fischer-Tropsch synthesis reaction. A device for Fischer-Tropsch synthesis includes a gasification device, an electrolyzer, a first gas washing device, and a Fischer-Tropsch synthesis reactor.