Abstract: Potato is a plant with high nutritional value that is at fifth place after wheat, corn, rice and barley in terms of production and consumption in world. Its production is increased due to high productivity and compatibility with a wide range of climates and as a nutritional source. In this study, silicon effect as a useful element on quantitative and qualitative performance of potato crop was evaluated in form potassium silicate. The experiments were performed in completely randomized block design with 3 replicates and in field conditions. For review was used of the concentration 0.5 mM of potassium silicate in solution and spray forms. The results of comparing mean traits showed significant differences between treatment groups in chlorophyll b, soluble sugars of leaves and carotenoids. Although, it was not observed significant differences between treatment groups in terms of chlorophyll a amount, leaves insoluble sugars and protein but spraying 5 mM potassium silicate showed significant increase in chlorophyll b amount and soluble sugars.