The invention provides a method for detecting pesticide residues through a paper-based visualized molecular imprinting biosensor, and discloses the visualized portable microfluidic paper chip sensor which is easy to operate and low in cost and is successfully applied to on-site detection. Through the sensor, a molecular imprinting technology is successfully introduced to a microfluidic paper chip, and color changing is triggered through a catalytic effect of zinc ferrite on hydrogen peroxide and 3,3',5,5'-tetramethyl benaidine to achieve visualized detection. The sensor is constructed through the following steps that hydrophobic patterns are printed in batches, wax melting forming is performed, and the zinc ferrite is prepared and synthesized; molecular imprinting polymers are synthesized in situ; a hydrogen peroxide solution is added to trigger a reaction, and the concentration range of the pesticide residues is determined by observing the color changes on the paper chip.