A data transmission method, wherein the method is used to transmit data between a first computer and a second computer, the first computer is a web server or an application server, the second computer is a database server, and comprises: the first computer receives a request sent by a browser or an application for accessing or modifying a database, putting, by the first computer, information required for implementing the request in the first data; sending, by the first computer, first data to a first image capture card through an image output port of the first computer; receiving, by the first image capture card, the first data; and sending, by the first image capture card, the first data to the second computer; or processing, by the first image capture card, the first data to generate second data, and sending, by the first image capture card, the second data to the second computer; wherein the first image capture card has an image input port, and the image input port is connected to the image output port of the first computer; and the image output port of the first computer is an output port of a display card of the first computer; and the image input port of the first image capture card, which is connected to the output port of the display card, is an image input port corresponding to the output port of the display card; sending, by the second computer, third data to a second image capture card through an image output port of the second computer; and sending, by the second image capture card, the third data to the first computer; or processing, by the second image capture card, the third data to generate fourth data, and sending, by the second image capture card, the fourth data to the first computer; wherein the second image capture card has an image input port, and the image input port is connected to the image output port of the second computer; and the image output port of the second computer comprises an output port of a display card of the second computer. the first computer is a web server or an application server, the second computer is a database server, and comprises: the first computer receives a request sent by a browser or an application for accessing or modifying a database, putting, by the first computer, information required for implementing the request in the first data; sending, by the first computer, first data to a first image capture card through an image output port of the first computer; receiving, by the first image capture card, the first data; and sending, by the first image capture card, the first data to the second computer; or processing, by the first image capture card, the first data to generate second data, and sending, by the first image capture card, the second data to the second computer; wherein the first image capture card has an image input port, and the image input port is connected to the image output port of the first computer; and the image output port of the first computer is an output port of a display card of the first computer; and the image input port of the first image capture card, which is connected to the output port of the display card, is an image input port corresponding to the output port of the display card; sending, by the second computer, third data to a second image capture card through an image output port of the second computer; and sending, by the second image capture card, the third data to the first computer; or processing, by the second image capture card, the third data to generate fourth data, and sending, by the second image capture card, the fourth data to the first computer; wherein the second image capture card has an image input port, and the image input port is connected to the image output port of the second computer; and the image output port of the second computer comprises an output port of a display card of the second computer. the first computer receives a request sent by a browser or an application for accessing or modifying a database, putting, by the first computer, information required for implementing the request in the first data; sending, by the first computer, first data to a first image capture card through an image output port of the first computer; receiving, by the first image capture card, the first data; and sending, by the first image capture card, the first data to the second computer; or processing, by the first image capture card, the first data to generate second data, and sending, by the first image capture card, the second data to the second computer; wherein the first image capture card has an image input port, and the image input port is connected to the image output port of the first computer; and the image output port of the first computer is an output port of a display card of the first computer; and the image input port of the first image capture card, which is connected to the output port of the display card, is an image input port corresponding to the output port of the display card; sending, by the second computer, third data to a second image capture card through an image output port of the second computer; and sending, by the second image capture card, the third data to the first computer; or processing, by the second image capture card, the third data to generate fourth data, and sending, by the second image capture card, the fourth data to the first computer; wherein the second image capture card has an image input port, and the image input port is connected to the image output port of the second computer; and the image output port of the second computer comprises an output port of a display card of the second computer.