Objective To investigate the level and associated factors of the self-management activation among young and middle-aged patients with thyroid cancer after surgery, and to provide reference for targeted intervention. Methods A total of 268 young and middle-aged patients with thyroid cancer after surgery were selected using convenience sampling and invited to complete a demographic questionnaire, the Patient Activation Measure (PAM), Social Impact Scale (SIS), and Acceptance of Illness Scale (AIS). Results The total PAM score was （57.48±16.57）, which was negatively correlated with the total SIS score and positively correlated with the total AIS score （both P＜0.05).Multiple linear regression indicated that, education level, 131I therapy, stigma, and illness acceptance were the influencing factors of activation in young and middle-aged patients with thyroid cancer after surgery （all P＜0.05). Conclusion The self-management activation of young and middle-aged patients with thyroid cancer after surgery is at the medium level.Medical staffs should formulate systematic and effective nursing intervention strategies according to the influencing factors, so as to improve patients′ the self-management activation.