1. A music playing system, suitable for playing music based on speech emotion recognition, the music playing system comprising: a first database, storing a plurality of songs and song emotion coordinates of the songs mapping on an emotion coordinate graph; a second database, storing emotion recognition parameters; a voice receiving device, receiving a voice data; a control device, connected to the first database, the second database, and the voice receiving device, analyzing the voice data, obtaining a current emotion coordinate of the voice data mapping on the emotion coordinate graph according to the second database, receiving settings of a target emotion coordinate, and searching for at least one specific song emotion coordinate closest to a cheer-up line connecting the current emotion coordinate and the target emotion coordinate in the first database.