Provided are a cryopreservation liquid for bovine reproductive cells such as bovine sperms and a cryopreservation method thereof. Adopted is a cryopreservation liquid comprising: 0.3 to 0.9 w/w% of an amphoteric polyelectrolyte (an antifreeze polyamino acid), which is ε-poly-L-lysine having a number average molecular weight of 1,000 to 20,000 wherein 50 to 99 mol% of amino groups of the ε-poly-L-lysine are blocked as carboxylated by having been reacted with the succinic anhydride； and 2 to 4 w/w% of glycerol, as dissolved in a physiological solution. A preferred embodiment of the cryopreservation method comprises steps of: primary diluting, in which bovine semen is diluted to 2.5 to 10 times with a physiological solution and kept at 2 to 8°C； and secondary diluting, in which the bovine semen is diluted to 5 to 20 times while being kept at 2 to 8°C, by adding dropwise a physiological solution containing the amphoteric polyelectrolyte (antifreeze polyamino acid) and glycerol to a suspension obtained in the primary diluting.
