The effect of reaction temperature, syngas space velocity, and catalyst stability on Fischer-Tropsch reaction was investigated using a fixed-bed microreactor. Cobalt and Manganese bimetallic catalysts on carbon nanotubes (CNT) support (Co-Mn/CNT) were synthesized via the strong electrostatic adsorption (SEA) method. For testing the performance of the catalyst, Co-Mn/CNT catalysts with four different manganese percentages (0, 5, 10, 15, and 20) were synthesized. Synthesized catalysts were then analyzed by TEM, FESEM, atomic absorption spectrometry (AAS), and zeta potential sizer. In this study, the temperature was varied from 200 to 280�C and syngas space velocity was varied from 0.5 to 4.5 L/g.h. Results showed an increasing reaction temperature from 200�C to 280�C with reaction pressure of 20 atm, the Space velocity of 2.5 L/h.g and H2/CO ratio of 2, lead to the rise of CO conversion from 59.5 to 88.2 and an increase for C5+ selectivity from 83.2 to 85.8. When compared to the other catalyst formulation, the catalyst sample with 95 cobalt and 5 manganese on CNT support (95Co5Mn/CNT) performed more stable for 48 h on stream. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.