Objective: To explore the influence of different exercise duration and types on immediate emotion and stress relief of college students, and clarify the optimal duration and type of exercise, so as to provide empirical evidence for the formulation of mental health promotion strategies in colleges and univeristies. Methods: From March to June 2025, a randomized controlled trial design was used to recruit 240 college students from 3 universities in Henan Province. The subjects were randomly divided into control group (rest), 5 minute exercise group, 10 minute exercise group and 15 minute exercise group by random number table method, with 60 students in each group. Each exercise group was further divided into 3 subgroups (20 students in each group):moderate intensity aerobic exercise, stretching relaxation, and core strength training, the intervention tool place from 16:00 to 18:00 . The Positive and Negative Affect Schedule (PANAS), State Anxiety Inventory (SAI) and Perceived Stress Scale-4 (PSS-4) were used to evaluate the immediate emotion and stress levels before and after intervention. Repeated measures ANOVA and multiple linear regression analysis were used to explore the intervention effect of short term exercise. Results: After intervention, the results of one way ANOVA showed that there were statistically significant differences in the scores of positive emotion, negative emotion, state anxiety, and perceived stress between each exercise group (5, 10, 15 min) and the control group ( F =58.63, 42.18 , 51.31, 47.83, all P <0.01). Further pairwise comparisons revealed that the improvement effects of the 10 min exercise group in each index (31.27±5.38, 12.15±4.08, 32.17±5.98, 5.64±1.98) were superior to those of the control group (22.98±5.30, 18.70±4.32, 42.52±6.25, 9.31±2.15) and the 5 min exercise group (27.65±5.42, 15.32±4.17, 36.84±6.07, 7.25±2.02) (all P < 0.05). There were statistically significant differences in the scores of positive emotion, negative emotion, state anxiety, and perceived stress among different types of short term exercises ( F =12.74, 10.68, 13.55, 11.21, all P <0.01). Further pairwise comparisons revealed that the intervention effects of the stretching and relaxation group and the moderate intensity aerobic exercise group were superior to those of the core strength group (all P <0.05). Multiple linear regression analysis showed that 10 minute moderate intensity aerobic exercise and 10 minute stretching relaxation could positively predict the improvement of positive affect ( β = 0.42, 0.39, both P <0.01), and negatively predict the levels of negative affect, state anxiety and perceived stress ( β =-0.37 to -0.34, all P <0.01). Conclusions Appropriate exercise duration and different types of exercise can significantly improve college students immediate emotional state and relieve acute stress. Among them, 10 minute moderate intensity aerobic exercise or stretching and relaxation is the optimal option for college students in short duration exercise scenarios, which can serve as an important supplementary measure for mental health promotion in colleges and universities.