Abstract: The instantaneous cutting rate of a roadheader is generally used to comprehensively measure the performance of the roadheader. It is important to select the roadheader as the tunnel excavation method as well as to select the type of the roadheader. To predict the instantaneous cutting rate of a roadheader, based on the instantaneous cutting rate which is mainly affected by both the lithology of the tunnel surrounding rock and the construction equipment factors, a prediction model is established by choosing the uniaxial compressive strength, rock quality designation and cutting power of the construction equipment as the prediction indexes. As the influence factors are fuzzy and uncertain, a prediction method of instantaneous cutting rate based on the fuzzy inference theory (including fuzzification, fuzzy rule base, fuzzy inference engine and defuzzification) is proposed. This method not only reflects the influence of the surrounding rock and the construction equipment, but also reflects the fuzzy uncertainty of the corresponding influence factors. Comparison of the predicted values achieved from the new model and previous model with the measured results shows that the proposed method is feasible and reasonable.