Incremental forming of sheet metals is a new method to produce parts in small batches. Since no die is used, relatively cheap equipment and also reduction of forming forces, parts with different sizes can be produced with lower cost in comparison with conventional methods like deep drawing. Due to low formability of Ti-6Al-4V at room temperature, forming of these sheets should performed at high temperatures. Simultaneous effect of heat generation and deformation can be realized in Electric Hot Incremental Forming of sheets. In this method, because of passing electric current through a closed circuit including voltage supply, spherical tool and sheet, local heat is produced at tool and sheet interface and by incremental movement of tool on the sheet, the desired geometry is formed. In this research Ti-6Al-4V sheet is experimentally formed by Electric Hot Incremental Forming method and effect of influencing parameters, namely initial sheet thickness, feed rate, spindle speed, tool vertical step size and amount of current passing circuit on formability and maximum forming angle of a frustum with varying wall angle is investigated. Amount of current entering the circuit has a significant effect on sheet formability and with increasing sheet thickness, amount of current required for deformation increases. Passing very high current through the circuit causes sheet burning and reduction of formability. It will be shown that a decrease in feed rate, step size and spindle speed and an increase in sheet thickness can increase maximum forming angle.