Multimedia in modern educational technology has the advantages of being infectious and easy to stimulate students’ interest, which can change students’ perception of things and enhance their mental health awareness when carrying out mental health education in higher vocational schools after analysing the advantages of the application of modern educational technology in mental health education. Taking the visual characteristics of multimedia learning screen as an entry point, we explore the internal logic and law of its influence on students’ learning emotions, hoping to use the learning screen carrying emotional value as an intermediate medium. Subsequently, a CNN-based emotion recognition model is constructed to analyse learners’ expressions, visual emotion preferences and the emotions of the learning screen, and adaptively adjust the key visual features of the learning screen so as to regulate the learners’ learning emotions, stimulate the learners’ interest in learning, and guide the learners’ emotional state. Based on this, a method of using intelligent multimedia technology to promote students’ mental health education is proposed. Combined with the results of teaching experiments, it can be seen that this paper’s innovative mental health education method has improved students’ positive academic emotions significantly, negative academic emotions improved to a certain extent, and the level of mental health has been further improved.