The purpose of this study is to propose an emotion recognition algorithm for piano music based on multimodal learning. Multi-modal learning is a learning method that combines various types of data. By combining different modal information, learning tasks can be completed more comprehensively and accurately. In the field of music emotion recognition, multimodal learning can extract the emotional features of music from different angles, and improve the recognition accuracy and robustness. In this study, the multi-modal learning method is mainly used, and the representative features are extracted by combining the audio signal, score information and the performance of the piano music, and the machine learning algorithm is used to classify the emotions. The audio signal is preprocessed, including noise reduction, cutting and other operations, and then the features of the audio signal are obtained by feature extraction methods, such as short-time Fourier transform (STFT) and formant analysis (RPA). Digitally convert the score, extract the structure, melody, harmony and other characteristics of the music, and obtain the emotional information of the music by analyzing the relationship between symbols and notes in the score. By analyzing the performance skills, strength, speed and other parameters of the player, the characteristics related to the emotional expression of the player are extracted. Machine learning algorithm is used to train and classify the fusion features, and the emotion recognition of piano music is realized. In this study, the emotion recognition algorithm of piano music based on multimodal learning can mine the emotion information of music at different levels, improve the accuracy and robustness of emotion recognition, and provide useful reference for the field of music emotion calculation.