Objective To construct and verify a learning motivation model for nursing undergraduates based on the self-determination theory. Methods A total of 467 nursing undergraduates were investigated by using the socio-demographic questionnaire, the Learning Climate Questionnaire, Basic Psychological Need Satisfaction Scale-in General, the Self-Regulation Questionnaire-Academic to collect the data of socio-demographic information, autonomy support, basic psychological need and relative autonomy index. A learning motivation model was built through the data. Results The model fit was satisfactory (χ2/df=1.954，NFI=0.979，IFI=0.990，CFI=0.989，RMSEA=0.045，SRMR=0.030). There was positive effect between either pair of the 3 variables (autonomy support, basic psychological need, and relative autonomy index). Three basic psychological needs (autonomy, competence and relation in descending order respectively) had predictive power on relative autonomy index (P<0.01 for all). There was positive effect of relative autonomy index on students′ academic scores (P<0.01). Conclusion As a model to understand the generation and development of learning motivation, self-determination theory can be applied to the population of the undergraduate nursing students.