Abstract: The ternary combination of dawsonite-corrensite-allevardite was found in the sand tuff and sedimentary tuff in the Cretaceous Nantun Formation of Hailaer Basin using the rock section and SEM and X-ray diffraction fine texture analyses. The three kinds of associated minerals have implied the characteristic mineral combination of volcanic tuffaceous alteration, which illustrated the reliable deposition of the contemporaneous palaeovolcano events and signified the diagenetic epigenetic alteration records in the volcanic tuffaceous matters transiting from the acidic environment to the alkaline environment. The secondary pores associated with the tuffaceous alteration could greatly improve the reservoir properties and extend the lower limit of exploration depth. The above-mentioned mineral combination is closely related to hydrocarbon reservoirs and is the important mark for searching the development zone of effective reservoir and hydrocarbon reservoir.