Keeping crude oil within the working temperature range in floating roof tank is the key to ensure safe operation of oil depot. Tubular heating is one of the conventional and extensive methods to heat crude oil. To improve flow and heat transfer performance of crude oil during heating process, a comprehensive numerical research is presented to investigate heat transfer and flow characteristics of crude oil in which heating tube is arranged with and without fins, and the impact of fin length and fin number on temperature field, flow field and heat flux of crude oil was investigated. The results show that increasing fin length, the average temperature of crude oil increases and inhomogeneity in temperature decreases. The most homogeneous temperature distribution is attained by tube with 200 mm length fin where maximum amplitude is 1.9 ºC. The improvement of heating performance with 4 fins is significant in the aspect of temperature distribution and temperature rise of crude oil. Moreover, the amount of heat flux at the tank wall decreases when increasing fin length and fin number, and maximum decrease is 4.39% for the tube equipped with 150 mm length fin, while other tank boundaries does not apparent changing rule.