Biochar, as a soil reclamation material, has received attention by researchers during recent decades. In this study, a greenhouse experiment was conducted in a randomized complete block design (RCBD) in factorial arrangement in order to investigate the effect of natural and municipal waste compost biochars on the chemical properties of sandy soils from Kashan's sand dunes. The experimental treatments consisted of natural and municipal waste compost biochar each with four levels (0, 1, 3 and 5%) with the total of 16 culture media. Chemical analysis was performed for soil, biochar, and for 16 culture media resulting from these combinations in three replications. The results of analysis of variance and comparing means of measured characteristics (EC, pH, Ca, Mg, K, and OM) showed that these characteristics were significantly affected by the different levels of natural biochars. Soil pH decreased in some treatments and treatment No 5 had the most pH reduction. Both biochar treatments increased soil EC, pH, Ca, Mg, and OM by 5.5, 3.9, 2.4, 1.9, and 3.7 times, respectively. In general, treatment No 13 (soil + 5% natural biochar + 5% municipal waste compost biochar) had the highest influence on soil characteristics. As a practical application, the use of studied biochars as sources of Ca, Mg, K, and OM can be considered in soil reclamation projects and fertilizer management.