The real circumstance of liquid metal as the pressure transfering agent during pressure casting was introduced.It is uncorrect to adopt the Pascar theory as the theoretical basis of pressure casting due to the ignorance of the adhersion effects resulting from strengthly temperature-reduction in the condition of high specific and intensively heat-exchange for liquid metal

so the good pressure-applying for thin-walled castings can not be realized.The new developing prospect on design and manufacturing of the die casting machine was predicted.