The invention provides a temporary group calling implementation method in a digital 
trunk system. The temporary group calling implementation method in the digital 
trunk system comprises the followingsteps: a 
trunk core network receives group calling establishment request information sent by a calling terminal, wherein the group calling establishment request comprises a specific number; the trunkcore network judges the requested group calling as temporary group calling according to the specific number, sends temporary group user 
list request information to a 
location information server and receives the temporary group user 
list sent by the 
location information server; the trunk 
core network creates a temporary group according to the temporary group user 
list and assigns a temporary groupnumber to the temporary group; the trunk 
core network pushes the temporary group information to the members in the group; and the trunk core network assigns calling identifiers, establishes the groupcontext, and sends group calling establishment response information to the calling terminal, wherein the group calling establishment response information comprises the temporary group user list. According to the temporary group calling implementation method in the digital trunk 
system, the calling process does not require a dispatching 
desk to participate, and does not write to the 
database, therefore, multiple dynamic regrouping operations in the temporary group calling implementation method in the prior art are avoided, and the process is simplified.