The development of new alternative type of pozzolanics soil bricks using the locally available clay from Ratchaburi province were mixed with fly ash from Kanchanaburi province, where both source in western of Thailand, is the main purpose of this study. These are compared to the local clay cement bricks without the mixing of flyash in different proportions. In the present work, the physical properties of the specimens are presented namely, compressive strength, modulus of rupture, thermal conductivity and unit weight. Tests were also conducted to study the influence of time of curing on the increase in physical properties of the bricks. It was concluded that the addition of fly ash reduces the thermal conductivity and unit weight, while increases the water adsorption property of the specimen. The compressive and flexural strength are decreased when the ratio of fly ash is more than 30 percentages. However, when considering the various factors it can be said that, appropriately ingredient toward produce to commercial of the good pozzolanics soil bricks is portland cement constant was 5 percentages and 30 percentages of fly ash by weight basis of soil at water per total powder, W/P 0.3525. The compositions of fly ash more than 25 percentages by weight basis of soil and since up to 14 days of curing time proved to be economical mixtures for load bearing panels or brick type structural elements according to the Thai Industrial Standard(TIS) for structural clay load-bearing tile. Therefore, commercial development is highly promising.