In this work, a series of hydroxylmethyl triamide (HMTA) was synthesized from vegetable oil, diethylenetriamine were and hexamethylenetetramine, which was evaluated as a crude oil flow improver. The results showed that HMTA has a good viscosity reduction effect on the crude oil from Yanchang Oilfield, with the highest viscosity reduction rate of 89%. The highest pour point reduction depression was achieved as 7.4 degrees C. Differential scanning calorimetry and paraffin crystal morphology characterization were conducted on the crude oil to elucidate the mechanism of viscosity reduction and pour point depression.