It is systematically analyzed that the effect,for the output and mode of lasers,of structure and correlative parameters of the three kind of resonators(flat-flat resonator,left concave-right flat resonator and right concave-left flat resonator)and left convex-right flat resonator of LD end-pumped solid-state lasers by the theory of transmit and transform circle. It is educed that laser with the shorter resonator outputs greater and the mode of laser beam is TM₀₀,and solid-state lasers with the left concave-right flat resonator and left convex-right flat resonator have the function of optical ballast. The result of experimenting with the solid state laser for the flat-flat resonator tallies with the analysis conclusion by the method of transmit and transform circle.