The invention provides a data interaction method, client and system. The method comprises the following steps: receiving a control command and a data file which are transmitted by a management end, and opening a modal dialogue box according to the control command, wherein the data file is acquired and resolved by a webpage engine to generate data coding information; loading the data coding information by the modal dialogue box to generate a dialogue box page, wherein a first communication channel is established between the modal dialogue box and the dialogue box page; and closing the modal dialogue box when a modal dialogue box closing command sent by the management end is received. The modal dialogue box is adopted, so that operation behaviors of the client are under the control of the management end, and various contents are displayed by the modal dialogue box. Through adoption of the data interaction method, client and system, the client of a user cannot optionally finish interaction outside the modal dialogue box during a working or learning process, so that the attention of the user is improved, and the processing efficiency of data interaction between the management end and the client is ensured.