Aim To explore the effectiveness of motivation‐guided ‘plan, do, check and action’ cycle nursing for self‐management ability and outcomes of patients with gestational diabetes mellitus (GDM). Design A pre‐ and post‐ comparison quasi experimental study. Methods Totally 108 pregnant women with GDM diagnosed and delivered in our hospital from January 2020 to April 2021 were included in this study. They were divided into study group (54 cases) and control group (54 cases). Results The score of self‐management ability were significantly higher than those of control group (t‐test, all p < 0.05), as well as themselves before interventions in both groups (t‐test, all p < 0.05). Besides, scores of anxiety, depression, extraverted stimulus and intraverted stimulus all achieved significant reduction after interventions in study group compared with control one (t‐test, all p < 0.05), as well as themselves before interventions in both groups (t‐test, all p < 0.05). Patient or Public Contribution No patient or public contribution.