Snow Spell is an interactive composition for erhu, flute, cello, piano, and Max/MSP interactive computer music system. This one-movement piece, Snow Spell, is intended to depict the beauty of a snow scene by presenting four different impressions of snow envisioned by the composer through music. The definition, history, and significance of interactive music are explored. Various modes of interactivity to control signal processing modules, and technical considerations for signal routing and level control in the interactive computer music system are also explored. Chinese music elements in Snow Spell including pentatonic scales, glissandi, and quotations from the Chinese folk tune River of Sorrow are investigated.