The present invention discloses a method for recovering a lost data unit, the method including: partitioning data to be transmitted into one or more data units, sorting the data units according to importance levels of the data units, and determining a check rule for the one or more data units, performing, by a transmitting end, a calculation on the sorted data units according to a predetermined algorithm depending on the check rule, to generate one or more corresponding check units; transmitting, by the transmitting end, the one or more data units to a receiving end in a sorted order, and transmitting the corresponding check units to the receiving end; recovering, by the receiving end, a lost data unit according to the receiving data units and check units as well as the check rule. With the method, the loss-preventative capability of the data units may be improved.