The invention relates to a safety isolation file transmission control method, in particular to a file transmission control method between taxation network safety isolation systems. A transmission control system comprises an external network isolation firewall, an external network control end, an external network transmitting end, an external network receiving end, an internal network transmitting end, an internal network receiving end, an internal network control end and an internal network isolation firewall. A computer system, a virtual machine system and the isolation firewalls are combined to achieved a relatively universal safety data transmission manner, safe and reliable bidirectional data transmission is achieved by the control method with a special safety protocol, confidentiality, completeness and non-repudiation during information transmission are achieved by safety techniques such as data encryption, digital signatures and information authentication codes, data exchanging performance is increased while safety of internal and external network systems is guaranteed, and the whole system can work reliably and stably.