The invention relates to a video decoding method and system based on a PCI multiple-head display card technology. The method includes the following steps that after an external network IP video data package receives IP package analysis and repeated package grouping, video data received in the IP network are divided into multiple paths of video data and the video package with the complete frame is constituted; the video is decoded in different formats by decoding SDKs of different manufacturers; the videos of different formats are converted into the RGB format through video system conversion; the DirectShow is used for controlling all paths of the videos with the RGB format to be output to the designated display card; the DirectDraw is used for controlling the PCI multiple-head display card to display, so that the video data in the IP network are converted into simulation videos and then output through the PCI multiple-head display card. The video decoding method and system based on the PCI multiple-head display card technology support control on video output by an external IP interface, outputting of the display card is controlled through a network interface message manner and thus, the requirements for large-scale video decoding access and concurrency of a certain amount are flexibly met.