In this paper, Ni70Mn25Co5 and Fe64Ni36 alloys and their composite alloys were used as catalysts to study the growth characteristics of typeⅠb diamonds grown along (100) crystal plane at different temperatures under 5.6 GPa pressure by high temperature and high pressure temperature gradient method. The results show that the diamond synthesized with Fe64Ni36 catalyst has a cracking growth zone of about 50 K in the high temperature growth range of (111) crystal plane. The diamond synthesized with Ni70Mn25Co5 catalyst is prone to crystal stock defects in the growth range, especially in the high temperature crystal growth range of (111) crystal plane. The excessive melting of Fe64Ni36 catalyst at high temperature may be the cause of crystal cracking, and the low viscosity of Ni70Mn25Co5catalyst melt may be the reason for easy formation of crystal stock. The combination of two kinds of catalysts can effectively avoid the formation of cracking and crystal stock. Raman spectroscopic characterization shows that the internal quality of crystal stock is similar to that of single crystals. There are more lattice distortion and impurities in the cracky crystals and the stress in the crystal is larger.The diamond crystal synthesized by compound catalyst system has low internal stress and good quality.