A bio-based UV-curable 3D printed resin includes the following components by weight percentage: 19-78% of biodegradable starch resin polymer, 1-9% of radical initiator, 0.2-4% of adjuvant, 13-62% of reactive diluent and 2-8% hydroxyethyl starch. The preparation method thereof comprises the following steps of: mixing the above components by component proportion, ultrasonically washing the mixture for 10-20 min by an ultrasonic cleaner under a water temperature of 50° C., and then mixing the same in a homogenizer homogeneously to obtain the bio-based UV-curable 3D printed resin. The renewable resources are adopted and the environmental pollution and energy consumption are reduced, which is of bio-safety. Moreover, the hydroxyethyl starch has a high molecular compound generated by hydroxyethylation of glucose ring of amylose, resulting in various benefits. The 3D printed resin obtained has excellent performance and low skin irritation value.