Numerically solving multi-marginal optimal transport (MMOT) problems is
computationally prohibitive, even for moderate-scale instances involving $l≥4$ marginals with support sizes of $N ≥ 1000.$ The cost in MMOT is represented as a tensor
with $N^l$ elements. Even accessing each element once incurs a significant computational burden. In fact, many algorithms require direct computation of tensor-vector
products, leading to a computational complexity of $\mathcal{O}(N^l)$ or beyond. In this paper,
inspired by our previous work [Comm. Math. Sci., 20, 2022], we observe that the costly
tensor-vector products in the Sinkhorn Algorithm can be computed with a recursive
process by separating summations and dynamic programming. Based on this idea,
we propose a fast tensor-vector product algorithm to solve the MMOT problem with $L^1$ cost, achieving a miraculous reduction in the computational cost of the entropy
regularized solution to $\mathcal{O}(N).$ Numerical experiment results confirm such high performance of this novel method which can be several orders of magnitude faster than
the original Sinkhorn algorithm.