After thousands of years of development and evolution, classical yoga has spawned many factions. Orthodox Indian "classical yoga" includes five systems: wisdom yoga, professional yoga, hatha yoga, raja yoga yoga and Kundalini yoga. The theories of different yoga factions vary greatly. Wisdom yoga advocates the cultivation of knowledge concepts; Yoga advocates inner practice and guides more perfect behavior; Belief in yoga is the synthesis and derivation of the former; Hatha yoga includes mental system and physical system; Raja yoga is inclined to mind and pranayama; Kundalini yoga focuses on the awakening and ascension of energy. Yoga with different system theories is a tool for practitioners to reach the spiritual world.