Abstract: Antileakage and lost circulation controlling material is the key to the protection of oil and gas formation, antileakage and lost circulation control. Antileakage and lost circulation controlling material XT lost circulation additive suited to the oil and gas formation was developed in lab, It ls made up of four kinds of material, there are either some particles with different size or some fibers with different behavior in it. The lab results showed thatXT is a kind of temporary plugging agent with high water loss and acld-solubility and has little effect on properties of drilling fluid and it is an ideal antileakage and lost circulationcontrolling material for producing formation.