Jam session means that several people improvise in a fixed harmony progression without prior rehearsal, mostly used as a term between jazz musicians, jam in the slang of black jazz musicians instead of improvise, and Jam session refers to several people improvising together.

Charlie Parker said that improvisation is speeded up composition, and composition is slowed down improvisation. Jam session is an indispensable subject for a musician, it can not only improve your skills and reactions, but also put the theory you have learned into practice, and it is also very helpful in grasping the integrity of music and the ability to cooperate with other musicians, which is the best way to train a musician's comprehensive quality.