In order to objectively and accurately evaluate the credibility of hydrodynamic torque converter’s flow field simulation model, 300 performance tests of one hydrodynamic torque converter were conducted, and a same number of simulation using the same input variables with the tests was also carried out. Results of both the tests and simulation were compared. Based on theory of complexity measurement, a credibility evaluation system covering three levels, including single-variable, dual-variables and multi-variables was set up, and corresponding quantitative credibility indexes based on complexity, relevance and robustness were put forward. The results showed that overall credibility of the simulation model was 72%. 