By the monitoring and chemical analysis of wet deposition at Liuxihe, Guangzhou, 106 rainwater samples with rainfall depth from 0.7 mm to 268.6 mm were collected and tested during the period from July, 2006 to May, 2008.The relationship between electrical conductivity(EC) and main ions' concentration in the precipitation was studied and discussed in this paper. The results indicated that:(1) Mean relative error between the measured data and the calculated data of EC was -2.94%.(2) The positive correlation between concentration of H⁺ and EC was found in the rainwater with pH<.5.6 and the negative correlation occurred in the rainwater with pH≥5.6.(3) EC increased with the increase of total ions concentration, nevertheless, when the H⁺ concentration and the total ions concentration were the same, there were also obvious EC differences among the rainwater samples duo to significant differences of chemical components.(4) After dividing rainwater into two groups(pH<5.6 and pH≥5.6), there existed better relations between EC and ion concentrations, so the concentrations of some ions can be calculated or forecasted by the regression functions and the measured pH value and EC.