In this study the effects of three important factors: the climatic precipitation, temperature and relative humidity on the amount of canopy cover and forage production in a period of five years (1381-1385) and 1392 in semi-steppe rangelands Reineh and Polur in the Mazandaran province studied. The statistical models (simple and multiple regression) to find the relationship between various forms of vegetative cover and annual forage plants using climate variables in different periods of time with Minitab.14 and Excel software was used for data analysis. The results of six years of study in a semi-steppe rangelands Polur and Reineh showed an average canopy cover of 51 percent and the average yield was 372 kg per hectare. The total vegetation cover of Rineh pastures had the most relation with a total rainfall of the growth season and the March and the average temperature. The temperature was more effectively than rainfall in annual yield. And The yield affected by July temperature. The total vegetation cover of polur had not significant relation with climate factors but each of the vegetation form in Different time base had significant relation. The total grazing species yield of plour affected by growth season rainfall. So instead of one year measurement of vegetation cover and production can be estimated the production and vegetation cover fluctuation according to climate parameters. With long-term vegetation cover and production data, can be determined the available forage and pasture capacity to prevent the range degradation.