The invention discloses a synthesis method of a PASP derivative with surface activity. The synthesis method comprises the following steps: s1, synthesizing polysuccinimide; s2, synthesizing a polysuccinimide derivative grafted and modified by
alkyl primary amine; s3, adding the
alkyl primary amine modified polysuccinimide derivative into a
hydrolysis kettle, adding water of which the
mass is 3-6 times that of the polysuccinimide derivative, stirring and dispersing, slowly dropwise adding 2-5mol / L NaOH solution for
hydrolysis under the heating and stirring maintaining conditions, and hydrolyzing at 35-65 DEG C for 2-6h to obtain a
hydrolysate, namely an
alkyl primary amine graft modified polyaspartate
aqueous solution; and carrying out pH adjustment,
filtration,
ultrafiltration, concentration and purification for further refining. The method is simple and easy to operate, and the
polymerization degree and the
grafting rate are regulated and controlled by regulating and controlling the proportion and the
chain length of the added alkyl primary amine compound. The synthesized alkyl primary amine modified
polyaspartic acid derivative has excellent surface activity and chelating property, and has the effects of moisturizing, removing freckles, whitening, improving
skin, removing
heavy metals and the like.