The invention discloses functional stitch-bonded non-woven fabric and a preparation method thereof. The functional stitch-bonded non-woven fabric comprises a hydrophobic layer I, a hydrophilic layer and a hydrophobic layer II which are stacked sequentially together, wherein all of the hydrophobic layer I, the hydrophilic layer and the hydrophobic layer II are made of hydrophobic fibers, hydrophilic fibers and hot-melt bonding fibers. The stitch-bonded non-woven fabric has function gradients comprising intensity gradients, moisture absorption gradients and antibacterial gradients and has the effects of breathability, high strength, wear resistance, tear resistance, moisture absorption, fast drying and bacterial resistance. The provided stitch-bonded non-woven fabric has a one-way moisture conducting property and can be used for manufacturing an insole of a shoe, and the comfort degree of feet is improved. Ramie-polyester blended materials are selected, the non-woven fabric has light and soft texture, high strength and good one-way moisture conducting effect and can effectively absorb moisture, moisture loss is avoided, a hydrophobic surface contacted with skin of feet is kept dry, and more comfortable feelings are brought to users using the one-way moisture-conducting product.