A system for monitoring variable parameters out of working parameters of a processing machine includes a selecting module, a frequency updating module, a first communicating module, a central processing unit (CPU), and a value processing module. The selecting module selects a number of variable parameters out of working parameters of the processing machine. The frequency updating module sets an updating frequency of the selected variable parameters according to the number of the selected variable parameters. The first communicating module converts the selected variable parameters into appointed formats. The CPU receives the converted variable parameters at the updating frequency, and gather the values of the received variable parameters. The value processing module receives the values of the selected variable parameters, and transforms the values of the selected variable parameters to display formats for presentation.