RTCP (rotation tool center point) is an advanced function of five-axis machining provided by five-axis machine tool. Maintaining the RTCP accuracy is of great significance to improve the machining accuracy of the machine tool. A feasible and straightforward RTCP error detection and compensation method was presented that the machine tool did not have a dedicated measuring device such as ballbar device etc. The empirical calculation formulas provided by the machine tool manufacturer was improved and the accuracy data before and after improvement were compared. The result illustrates that the proposed way is feasible.