In high power laser diode (LD) end-pumped solid-state laser, due to the complicated interaction between pump optical field distribution and thermal effect, the method of analysis thermal effect used in low power cannot be used, or leads to large error. In the light of the above, the concept of iteration used in calculation method can fully consider the interaction between pump optical field distribution and thermal effect. So, the interaction in some typical LD end-pumped solid-state laser is analyzed, and the calculation error without considering the interaction is studied. At the meanwhile, by comparing abortion length of solid-state laser material with its effect focal length, a parameter K is put forward to measure intensity of the interaction, and it can be used to judge whether considering the interaction or not. The results show that when the parameter K is less than 0.1, the influence of the interaction is below 3 percent.