The invention relates to a rain gauge for measuring multiple parameters such as pH. The rain gauge is characterized by comprising a rain bearing barrel, a laminar flow meter, a case, a metal beam bracket, an elastic conical sealing gasket, a capacitance micro difference transmitter, a pH measuring system, a temperature/turbidity measuring system, a wind speed measuring system, an intelligent display system and a transparent water-proof membrane. The rain gauge has the advantages that: the conventional rain storage bottle is replaced by the laminar flow meter, so that continuous running of an instrument becomes possible; the rain gauge is made of a high-intensity, low-density and rust-proof material, so that convenience is brought to field operation and manufacturing cost is lowered greatly; advanced new pH, temperature/turbidity and wind speed measuring technology is integrated, so that technical advancement is improved greatly; and corresponding measured results of rainfall, pH, temperature, dust content (turbidity) and wind speed are displayed on an axis y at any unit time on an axis x of a coordinate, so that the measured results are undoubtedly more accurate and more complete compared with that of the conventional single method for measuring the rainfall and rainfall intensity in the unit of minute.