Abstract: In technological design of tank farms, calculation has to de made in regards to heating viscous oil in tanks. The article deals with the heat conducting process of heated oil and detailed calculation. Because of a greater number of technological parameter variables, trail calculation is generally carried out to deal with it in engineering. which not only duplaicates the calculation processes, but also takes quite a long time. The article makes out a programme with frame diagram and put it into the Apple-Ⅱ computer for calculation, which is possessed of such advantages as being fast, accurate, convenient and common. In the end, examples are cited to show the calculation process by use of micro-computers.