The invention provides a combined centrewall of a ring spinning frame. The combined centrewall comprises a centrewall body (1), L-type positioning plates (4) arranged at the two sides of the centrewall body (1), positioning spigots (9) are formed in the two outer side faces supported on the lower portion of the centrewall body (1) respectively and are used for reducing width of the centrewall body (1), positioning faces (10) are arranged on webs at the two sides of the centrewall body (1) in the thickness direction respectively, and the L-type positioning plates (4) are fixedly connected with the positioning spigots (9) and the positioning faces (10). The combined centrewall of the ring spinning frame has the following advantages that the centrewall structure in the prior art is improved, the width of the two outer side faces supported on the lower portion of an original centrewall is reduced, the L-type positioning plates are installed, the middle and lower portion of the centrewall extends downwards to install a fixed hinge supporting base so that an integral cosine doffing device can be installed on the centrewall, it is not needed to replace the centrewall, the manufacturing cycle is shortened, and the cost for modifying the integral cosine doffing device is reduced.