In recent years, the application of digital textile printing has increased. The benefits of using this method include the ease of sampling and the production of printed textiles. However, the production process of digital textile printing differs from that of conventional printing. For successful digital textile printing by ink-jet technology, the pretreatment of fabrics is very important in order to overcome the following problems. Low viscosity ink can spread easily on the textile surface leading to poor resolution. As a result, the combination of ink and pretreatment chemicals is still impractical and consequently most fabrics used in digital textile printing will require a pre treated coating in order to prevent the ink colours from bleeding on the fabric. Research presented in this paper shows some preliminary attempts to establish the relationship between the pre treatment and the digital textile printing quality. Various cotton fabrics were treated with pre treatment agents including ingredients like thickener, alkali and humectant, and then ink spread effect and colour yield of printed fabrics by reactive ink were analysed by using an optical microscope and K/S value. The results show that digital textile printing quality on cotton fabrics can be optimized with appropriate pre treatments.