The present invention, relating to the field of network technologies, discloses a data communication method and device and data interaction system based on browser. The method includes: receiving request data input by a user by using a browser; generating a request data packet using the request data according to a preset private protocol; and sending the request data packet to a server. The client includes: a receiving unit, a generating unit, and a sending unit. The data interaction system includes a client and a server. According to the present invention, a request data packet is generated for request data according to a preset private protocol, and then sent to a server. In addition, during the data communication process, other protocol-specific fields in HTTP are not carried, thereby reducing data transmission amount, saving bandwidths, and improving data transmission efficiency.