The rheological behaviors of a pH-switchable wormlike micelles system formed by Sodium Oleate/Triethylamine Hydrochloride were investigated by rheology method. Though steady-state and dynamic rheological measurements, it was found that at 30℃, when the pH value is cycled between 8.20 and 9.40,the viscosity of the NaOA(0.12mol稬-1)/ Et3NHCl(0.2mol稬-1) solutions vares without any deterioration to its response more than three times between 3 and 27649 mPa稴,and also its rheological behavior complies with Maxwell model. These pH-stimuli rheological properties were attributed to the effect of pH on the interaction between NaOA and counterions Et3NH . Upon decreasing pH, the micellar surface charge density was decreased due to lowing of counterions Et3NH ionic strength, leading the micelles grow continuously .while upon decreasing pH to 8.64, flocculation occurs due to the attractive interactions between adjacent micelles. However, on increasing pH to 9.40, the micellar structures were destroyed due to counterions Et3NH desorbing from the surface of the wormlike micelles.