Abstract: Aiming at difficult features in welding stability evaluation, a kind of welding stability evaluation method based on the current entropy was proposed. The mean and the standard deviation of sample entropy and was increased when current stability decreased. The product of mean value and standard deviation of the sample entropy were selected to quantified the welding stability. The effects of embedding dimension, given threshold and sample length on the sample entropy were discussed. For the given pulse MIG welding current signal, sample entropy distributed reasonably and time consumed less when m=2, r=0.08, N=2 000. Three contrast pulse MIG welding experiments were carried out at last and the results indicated that the welding stability evaluated by product of sample entropy mean and sample entropy standard deviation was coincided with actual weld quality, high value of the product of sample entropy mean and sample entropy standard deviation reflected inferior welding stability when the current was tbe same.