The invention discloses a method for remotely accessing a private network device. An HTTP interface lookup-ip of an IP inquired according to a domain name is added to a DNS server, the flow of remotely accessing the private network device is optimized, and the problem of accidental connection interruption of a DDNS device caused by a DNS cache problem in the process of remotely accessing the private network device is solved by an optimization strategy combining DNS domain name resolution with HTTP interface inquiry IP; and on the other hand, on the basis of the standard DDNS scheme, the invention provides the concept of an extranet domain name and an intranet domain name, the intranet IP is reported while the extranet IP is reported, both of the extranet IP and the intranet IP can be obtained by DNS analysis, thereby solving the problem that when an access end and an accessed end are located in the same intranet, the router does not allow network access retracement, such that the access end cannot access the device through the extranet IP.