Mass exchange between the layers in a numerical model should follow the mass conservation principle when dry convection happens in atmosphere. By use of this principle, the dry convection adjustment scheme in thep－σ regional climate model is improved. The improvement is mainly to adjust specific humidity and wind at the same time when temperature is adjusted. By use of the 1979－1995 NCEP/NCAR reanalysis monthly mean data, two simulations of the climate characteristics in January and July are conducted, one is to use the original adjustment scheme and the other the newly developed scheme in this paper. The modeled results are compared with each other. Furthermore, the F and t tests are utilized to examine the confidence levels of their differences between the new and the old methods. The results show that in both months, the adjusted areas are not evidently affected by the new scheme, but the times of adjustment increases in the new scheme. The F and t tests indicate that the differences between the two simulations are more obvious in July than in January. Moreover, the general mean climates of precipitation and specific humidity are not obviously different, but the differences of their variances are much more remarkable. As far as the temperature and the wind are concerned, the general mean climates and the differences of their variances are all very prominent. The sensitivity experiment with the new scheme shows that the simulation of wind field from 20°N to 35°N at 500 hPa in July is improved outstandingly; as far as the simulation of the precipitation field in July, the areas with false large-value precipitation in the north of Xinjiang, the vicinity of Hohhot, the east of Jilin, Hubei and Guangdong are eliminated.