The invention discloses a method for preparing a placenta preservation solution. The method includes the following steps that firstly, a 0.9% sodium chloride aqueous solution is prepared; secondly, an AIM-V serum-free medium is added into the solution obtained in the first step to form a preservation solution; thirdly, NaHCO3 is added into the preservation solution obtained in the second step, and the PH is adjusted to be 7.1-7.4; fourthly, the preservation solution obtained in the third step is filtered through a filter membrane with the aperture of 20-25 micrometers, and finally the placenta preservation solution is obtained. The placenta preservation solution is prepared from the 0.9% sodium chloride aqueous solution and the AIM-V serum-free medium, cell osmotic pressure and activity can be effectively maintained, cell immunity is improved, the placenta preservation solution has no toxic and side effects on cells, the placenta preservation solution is simple in component so that preparation can be convenient and quick, and the utilization rate is increased.