Introduction: Soil tensiometer is made up of pressure gauge, acrylic tube and ceramic probe, after the acrylic tube filled with water, ceramic probe gets wet and it can prevent outside air into the ceramic probe. When there is pressure difference between measured soil water potential and tensiometer, the water in tensiometer will infiltrate into the measured soil until the balance reached. So at that moment, the value shown on the pressure gauge is the measured soil water potential.