The present study provides insight into the effect of experimental operations on the Fischer-Tropsch synthesis (FTS) product distribution by combining experimental and theoretical analyses of the process. Experimental errors originated from GC data processing and product collecting conditions are addressed here based on the experimental data obtained using commercial iron-based catalyst in a tubular fixed-bed reactor. A corrected area normalization method, which is a combination of the area normalization and simulated distillation, is proved to be an accurate and convenient method for FTS heavy oil chromatogram quantification. The flash loss from the hot trap and the cold trap is found to be negligible under the normal operating conditions. However, water may be condensed remarkably in the hot trap at low temperature and wrapped by wax. In addition, the selectivity of the high-carbon-number alcohols will be seriously underestimated at low temperature of the hot trap. The FTS product distributions under a wide range of reaction conditions are exhibited.