It was found in this work that silicotungstic acid hydrate could be mixed with phosphoric acid (H3PO4, 85%) to make a viscous paste material with high conductivity (10(-2) S/cm at room temperature). The STA/H3PO4 paste samples were stable at 80 degreesC in the atmosphere, and at 100 degreesC under constant humidity over 10 days. The conductivity behavior of the paste samples has been investigated under various conditions, and it was found to be dependent on temperature, paste composition, and environment humidity.