Groundwater quality comprises the physical, chemical, and biological qualities of ground water. The pir-e-Qar spring, located in the Zagrus mountains Iran have been considered as an important water source for people in the area southwards. We used data samples water quality (SAR, Cation+, Anion-, EC, TDS, Cl, Mg, Na, CaSo4 and Hco3) and discharge at 1987-2013 period. The results M-k test show that Hco3,Cation+,Anion-,Cl,EC and TDS have upper ward but discharge has downward trend at period(1987-2013). Other results show that the calculated Z element Hco3, Cation+, Anion-, Cl, EC and TDS are z ≥ + 1.96 that these amounts show elements have upper ward . There is enough evidence to determine that there is an upper ward trend. The calculated z discharge is -3 that it was ≥ - 1.96. Discharge has down ward trend there is not enough evidence to determine that there is a downward trend at Pir-e-qar spring