The inner engagement globoidal cams mechanism is put forward in this paper. Based on the matrix transformation theory and the conjugate engagement theory of spatial mechanism
the surface equation and pressure angle equation of the inner engagement globoidal cams mechanism are attained.The software of the three dimensional modeling of the inner engagement globoidal cams is programmed based on the UG/open module of UG software and verified through an example.The inner engagement globoidal cams mechanism can be used for the high efficency and high torque speed reducer