In this study, the Taguchi and symmetric quasi-D optimal methods were applied to comprehensively evaluate the influence of a wide range of factors affecting worm drive efficiency: oil kinematic viscosity v, friction coefficient f, rotational speed n, speed ratio u, output torque T2, module m, and diameter factor q, thereby choosing an appropriate method when studying the efficiency of mechanical drives and also choosing an optimal parameter domain to ensure maximum efficiency when designing, manufacturing, and operating the worm drive. Quadratic regression equations were obtained for the most influential factors, and the results showed a high goodness-of-fit and accuracy. Experimental models were developed to evaluate and compare the effects of the factors on efficiency. Overall, the regression equations can be used to predict the efficiency of worm drives and to select the parameters that improve the efficiency of worm drives or help develop new worm drive products. The worm testing system can be used to test the efficiency of worm drives or develop new worm drive products.