This paper presents an experimental investigation for the parameters affecting the properties of the geopolymer (GP) based materials. The investigated parameters included the molarity of the sodium hydroxide NH (10, 12, 14, 16 and 18 molar), the sodium silicate to sodium hydroxide ratio NS/NH (0.5, 1, 1.5, 2, 2.5 and 3.5), the adding of extra water as a ratio of fly ash (0 and 10%), the curing temperature (40, 60 and 80 o C), and the rest period (0 and one day). As, the production of GP based materials mainly require heat curing, thus this research is also studied the effect of using solar energy in curing and the results were compared to the traditional thermal curing. Both of the fresh and mechanical properties were evaluated. The results showed that increasing the molarity of NH enhanced the compressive strength and molarity of 18 gave the highest compressive strength. Moreover, NS/NH of 2 achieved the best compressive strength. Whereas, using of extra water influenced both of fresh and mechanical properties as it improved the first and reduced the second. On the other hand increasing the curing temperature enhanced the early age compressive strength whereas the final one is dependent of time- temperature history. Moreover, compressive strength of GP mortars cured in ambient environmental conditions can achieve the compressive strength of those cured with traditional thermal curing.