The invention provides serum-free preservation liquid for umbilical cord mesenchymal stem cells and application of the serum-free preservation liquid. The serum-free preservation liquid comprises normal saline with a NaCl mass fraction of 0.85-0.92%, insulin, estrogen, progestogen, hydrocortisone, sodium selenite, adenosine, N-acetylcysteine and L-glutamine. The insulin, the estrogen and the progestogen are added into the normal saline. Compared with serum preservation liquid, the serum-free preservation liquid and the application have the advantages that material sources capable of generating harm due to toxin with diversified components can be reduced to the greatest extent; the serum-free preservation liquid contains functional components with few components, basal metabolism of the cells can be maintained, and the cells are smooth in performance without huge variation; certain basic active nutrient substances and energy substances can be provided by the components, so that low metabolism level can be kept, the activity of the cells is in a stable state, shape variation or differentiation or the like due to growth and cultivation can be prevented, protection effects can be realized for the cells, the activity and the quality of the transplanted umbilical cord cells can be kept in a long-acting manner, and transplanted cell therapy clinical effects can be improved.