provided are a method and a device of a host with ipv4 application for performing communication . the method of the host with ipv4 application for performing data communication includes the following steps : the ipv4 application generates an ipv4 packet sent to a communication end ; when confirming the type of the network the host is located in is an ipv6 network , the host transforms the ipv4 packet head of the ipv4 packet to an ipv6 packet header , and sends it to the communication end via the ipv6 network . with this invention , it can be accomplished that according to the type of the network the host is located in , the host with ipv4 application communicates with a communication end ; the processing load of the system is lightened ; the probability that invalidation occurs at a single node is reduced ; the smooth migration and transition from original ipv4 application to ipv6 system are facilitated .