Geopolymer concrete is another option now-a-days to use instead of Ordinary Portland Cement concrete, as geo-polymer concrete is ecofriendly concrete because it does not produce carbon during its production. In Geo-polymer concrete various minerals and admixtures can be used according to design and availability of minerals. In this paper Potassium Feldspar powder is going to be used along with flyash. Potassium Feldspar powder (PFP) is used as raw material in ceramic and glass industries. Potassium Feldspar powder has high silica and alumina content and can be used as one of the source material to develop Geopolymer concrete. The study will focus on combine effect of PFP and fly ash in Geopolymer concrete. In this study the PFP is replaced with flyash in ratio of 10%, 20% and 30% to develop Geopolymer concrete. The experimental study measured the mechanical and durability properties of Geopolymer concrete and optimum percentage of PFP to get strength of M35. In the results, it is observed that the 7 and 28 days compressive strength of the specimen increases in the 14M solution and 16M solution desired strength M35 is achieved while the strength decreases in 12M solution for 20% replacement. The replacement of PFP upto 20% in recommended for 14M and 16M solution.