Non-porous carbon sphere was used as support to synthesize supported cobalt Fischer-Tropsch catalysts with high activity and durability. Strong metal-support interaction was avoided and intrinsic activity of pristine cobalt nano-particles was studied. Thermal decomposition synthesis method was applied to ob-tain cobalt catalysts with high dispersion and narrow particle size distribution. Furthermore the cobalt size can be controlled by the molar ratio of o-dichlorobenzene/ benzylamine. Compared with supported cobalt catalysts prepared by incipient wetness impregnation method and ultrasonic impregnation method, the catalyst prepared by thermal decomposition method showed higher catalytic activity, higher long chain hydrocarbons selectivity and lower methane selectivity.