The invention relates to a multi-loop cable steady-state temperature rise acquisition method adapting to various boundary conditions. The method comprises the following steps: 1) constructing a multi-loop cable steady-state temperature rise model adapting to various boundary conditions according to a thermal field superposition principle; 2) acquiring an initial temperature rise matrix T<0> according to a set initial heat flow matrix Q<0>; 3) performing reduction according to the initial temperature rise matrix T<0> and the boundary conditions to form a reduced heat flow matrix Q<1>; 4) acquiring a next-step temperature rise matrix T<1> according to the reduced heat flow matrix Q<1>; and 5) judging whether a maximum difference value among all elements which correspond to the initial temperature rise matrix T<0> and the next-step temperature rise matrix T<1> is greater than a convergence threshold or not, if so, substituting T<0> with T<1> and returning to the step 3), and otherwise, judging that a current corresponding temperature rise matrix is a steady-state temperature rise matrix. Compared with the prior art, the multi-loop cable steady-state temperature rise acquisition method has the advantages of easiness and accuracy in calculation, high calculation efficiency, advanced algorithm, adaptability to various boundary conditions, and the like.