Objective: To analyze the situation and associated factors of school lunch leftovers of primary and middle school students in Ningbo, so as to provide a basis for formulating policies to improve the quality of nutritious meals and reduce the leftover meal rates. Methods: During March to May of 2022, 20 primary and middle schools were selected from 10 districts in Ningbo, and 4 443 students were selected from grade 4 to 6 of primary school and grade 1 to 3 of middle school. A questionnaire was conducted among them for the students general situation and remaining meal situation. Results: The total leftover rate was 62.4%, 7.9% of the students left rice every day, and 18.3% of the students left vegetables every day. The frequency of primary school students leftover food was lower than that of junior high school students ( χ 2=-2.18, P <0.05). Most of the students (68.3%) had only a little leftover food, half of the students (49.4%) had less than half leftovers, and the proportion of primary school students with large leftover food and leftovers was smaller than that of junior high school students ( χ 2=-2.05, -2.36, P <0.05). The main reason for students leftover food was "too much to eat" (accounting for 30.6%), and there was a statistical difference between primary school students and junior high school students in the composition of leftover food and leftovers ( χ 2=16.94, 14.28, P <0.05). The leftover rate of vegetables was the highest (54.5%) and the leftover rate of milk was the lowest (2.5%). Multivariate Logistic regression model showed that nutrition and food related courses during recent year, being aware the Chinese residents dietary guidelines, statisfaction with canteen food (general, more satisfied, very satisfied), reckoning school canteen food better than home food (almost, better than home) were less possibility to have leftover meals ( OR=0.79, 0.73, 0.57, 0.41, 0.26, 0.69, 0.82, P <0.05). Students chosed the meal after the teacher served the meal, the teacher divided meals and students who ate more frequently (4-6 times/week, 1 time/d, 2 times/d, ≥3 times/d) were more likely to have leftover meals ( OR=1.64, 2.23, 1.27, 1.21, 1.52, 1.44 , P < 0.05). Conclusion More than half of the students have leftovers. It should optimize the configuration of nutrition lunch, strengthen the education of nutrition knowledge and reduce the leftovers rate.