Intention preservation of operation is a new proposed concept in the field of CSCW (computer-supported cooperative work), and the key feature of consistency control. A new called document marking scheme for intention preservation is proposed in this paper. By properly marking the sharing document, the document marking scheme can hide the effect of all concurrent operations of one operation. Therefore, operation can be performed at any cooperative side under the document environment just like it produced. Associating operations in a real-time cooperative editing system, the idea and the high-level control algorithm of the new method are presented in detail.