According to seismicity hazardous drawing of the word, two main faults are passing through Iran. These two faults have made Iran as one of the most probable seismic countries in the word. The history of recent earthquakes in Iran indicates that almost every 10 years one destructive earthquake has occurred during the last century which caused vast destruction of buildings and death of the residents and major economical damages. Due to developed use of masonry materials and also many traditional and historic buildings in Iran, reinforcing of masonry buildings is necessary. Using traditional methods of buildings reinforcement, require long execution time and is difficult to perform and also hold the operation of the buildings. In recent years using cement composites like ECC in the buildings reinforcement is considered extensively by the researchers. In this study using ECC composite, which is a mortar reinforced by strain hardening fibers, as the tension strength element, has investigated in increasing formability of non reinforced masonry walls. In the first part of this study the effect of substituting cement by pozzolanic materials like fly ash, micro silica, nano silica and cement like slag material has investigated on tension properties of ECC mortar at the age of 28 days under direct tension test. The results of direct tension test showed that using cement substitute materials have positive effect on tension properties like strength and formability of ECC mortar. While micro silica and nano silica are more effective for strength properties, slag and fly ash have more effect on tension properties of ECC mortar. In the second part of this study, after choosing the proper mixing design of ECC, 6 masonry walls with the dimensions of 900×900×100 mm constructed. One of the walls was kept as the sample and the other 5 walls reinforced on one side or two sides along the tension diameter using various bands of ECC layer thicknesses. Performing the diametric pressure test on the walls, the effects of ECC mortar on strength and in plane formability properties of the specimens have studied. The tests results showed that doubling the ECC bands thickness, the maximum shear strength and formability have increased by 71% and 126% with respect to the sample specimen. Despite variations in the wall failure in out of plane bending, the ECC bands had considerable effect on one sided reinforcement of masonry walls by increasing the maximum shear strength and formability by 25% and 44% respectively with respect to the sample specimen. Keywords: Masonry building, ECC mortar, Pozzolanic materials, Direct tension test, Tension properties, Formability, Maximum shear strength