Solar energy is the major factor to generate sustainability and yield advantage on peanut (Arachis hypogaea L). An experiment to study the growth, yield and conversion efficiency of radiation energy (CE) on the varieties and different plant population of peanut was carried out on gray alluvial soil at Jambegede Research Farm, Indonesian Legume and Tuber Crops Research Institute, Malang, East Java, Indonesia, from July to October 2011. It was located about 335m of upper sea level. The experiment was arranged in a Split-Plot Design with three replications. Peanut varieties for the main plot consisted of two treatments: Kelinci and Kancil. Five different plant populations for the sub plot consisted of 44.4 m^-2, 25.0 m^-2, 16.0 m^-2, 11.1 m^-2, and 8.1 m^-2. The growth, yield and CE value were monitored during the growth period of two varieties of peanut. The results indicated that total Dry Weight (DW) of Kelinci variety (1114.91 g.m^-2) was higher than that of Kancil variety (1018.62 g.m^-2) and the highly different plant population increased the total DW value. Thus, peanut varieties and different plant population of peanut had significantly affected CE value. Total DW during vegetative and early generative growth increased with increasing leaf area index (LAI), crop growth rate (CGR) and CE value. The main factor which affected DW production among other plant populations was LAI value. The component associated with economic yield at maturity in peanut was harvest index (HI). The CE value of Kelinci variety (1.52%) was higher than that of Kancil variety (1.41%). The plant population 44.4 m^-2 would help increasing CE value on both of Kelinci and Kancil varieties.