Abstract: This paper first introduces the principle of the algorithm——orthogonal-Trhngular Decomposition (OTD). Then it discusses some problems encountered when using OTD in bundIe adjustment with special reference to the characteristics of the design matrix. One of the obvious advantages of OTD is the good solution of the problem "strict and fast calculation of redundancy bunrbers", which has hitherto aroused much attention. OTD has greatly simplified the calculation of Q_ⅴⅴ elements. It is superior to the other algorithms in numerical stability and calculation time. The results of a set of tests show that the OTD is a valuable algorithm.