The invention provides an editable multi-level tone synthesis system and method. The synthesis system is used to edit and synthesize tones of different levels of a musical instrument, simulate different tone effects generated by a note of the same pitch in different playing conditions, and further simulate real tones of musical instruments; and the playing condition is one or multiple selected randomly from the type of the musical instrument, a manufacturer of the musical instrument, the model of the musical instrument, the individual of the musical instrument, a player or a playing object and a playing technique. The synthesis system comprises a tone characteristic unit, a tone editing unit and a tone synthesis unit. Thus, different levels of tones that can be played by traditional physical musical instruments can be simulated more accurately, and a higher-end of electronic sound source can be generated; and different source tones of different levels can be mixed and edited to generate a new sound source, the musical expressive force of the electronic musical instrument is enriched, and the source tones of different levels can be tones of the same fundamental frequency from the same or different musical instruments.