Jam session means that several people perform impromptu (improvise) in a fixed harmony (progression) without pre-rehearsal, mostly used in terms between jazz musicians, and jam replaces improvise in the slang of black jazz musicians, while Jam session refers to several people impromptu together. Charlie Parker (Charlie Parker) said that improvisation is an accelerated composition, and composing is a slowing improvisation. Jam session is an indispensable subject for a musician. It can not only improve your skills and reactions, but also practice the theory you have learned. It is also a very helpful group in grasping the integrity of music and the ability to cooperate with other musicians. It is the best way to train a musician's comprehensive quality.