The invention discloses a method for dynamically allocating the cycle of the related retention blocks, which relates to the general group wireless service of 2.5-generation of mobile communication and resolves the problem that the length of block influences the transmitting rate up and down. In the method, the group controlling sell sends the valid wireless-link controlling data-block containing cycle information to the mobile station, and judges whether there is a loss of the data block according to the grouping conforming information received from the mobile station. If there is, the cycle of the related retention block will be shortened within the threshold value, if not, the cycle will be extended. |