The invention discloses a real-time warning system and a real-time warning method of a B/S framework in an electrical power system. The real-time warning system comprises a data collecting module, a data processing module, a warning serving module and a browser displaying module. An AJAX (asynchronous javascript and xml) long connecting mode is adopted in the real-time warning method to realize requests of warning messages, and warning message refreshing is performed by judging whether new data exist or not; if a new warning message comes to a server side, the system receives and displays the warning data and sends new AJAX requests; if no warning messages exist in a period of time, then the connection is in a sleep mode and waits until new warning data come or next AJAX requests are sent when requests are overdue. By a new real-time information transmitting method, the real-time scheduling and warning service system of the B/S framework in the electrical power system is realized; and by the aid of imaging method, visual display of vast history real-time data in Juniper real-time data base is realized.