In order to study the function of fodder in the mixed farming of sun flower, fodder corn, Sorghum and pearl millet in the climate of Damghan the experiment was performed in form of the randomize completely blocks design with three replication a year in 2011 farming year single crop planting and mixed crop planting in two, three and four planting that the proportion of planting included 25, 50, 75, 100 percents. In this experiment some manners such as the altitude of plant , number of leaves , length of leaf, width of leaf , the dry a fresh function ratio were determined and then the variance analyzing and comparing averages were performed by some extend Duncan test by 5% possibility and finally the collocation co efficiency among the manners were determined by SAS statistics soft ware. The comparison of averages showed that the most fodder function is related to the mixed farming of corn and sun flower with 201.57 tons a hectare and the best dry function was related to the mixed millet corn and sun flower with 54.85 ton in a hectare and the least function was related to the millet 22.26 ton in a hectare and the collocation co efficiency between the width of leaf with the positive fresh function and it was meaningful with the possibility level of one percent. (r= 0.64**).
