The invention provides an auxiliary carrying tool for drilling and completion pipe strings, and relates to the technical field of site construction of petroleum drilling and completion pipe strings. The auxiliary carrying tool comprises a framework body (1), a tool support mechanism, a lifting mechanism and a travelling mechanism, wherein a group of sliding chutes are formed in the framework body (1); the tool support mechanism comprises a roller stand (2) and two groups of support rollers (3); the roller stand (2) slides up and down in one group of sliding chutes formed in the framework body (1); the two groups of support rollers (3) are respectively and movably installed at the two sides of the roller stand (2) by a bearing, and an arc-shaped support surface is formed by the tops of each group of support rollers (3); the lifting mechanism is installed between the framework body (1) and the bottom of the roller stand (2); the travelling mechanism is movably installed at the bottom of the framework body (1). The auxiliary carrying tool is simple and reasonable in structural design and low in manufacturing cost, and can meet the site construction requirements of assisting to carry the drilling and completion pipe strings, adjusting the heights of the pipe strings and enabling the pipe strings to freely rotate, thus having very high application value.