The present invention is digital ink jet fabric treating process, and belongs to the field of textile science and technology. The fabric pre-treating process for digital ink jetting and printing with water thinned pigment ink is suitable for fabric of cotton, hemp, silk, Dacron, polyester and cotton blend, acrylic fiber, etc.; and the treated fabric may be ink jetting printed with water thinned pigment ink in one digital ink jetting printer. After printing and proper heat treatment, may be produced printed product with clear pattern, bright color, and high fastness to resist water washing, friction and sunlight.