Abstract: To ensure the representativeness of coal mechanical sampling,it is necessary to verify representativeness of mechanical sampling device.The precision of sampling is verified and counted by replicate sampling method,the results are used to evaluate if the sampling precision meet the expectations.The precision of the sample preparation is verified by the standard deviation counted by two groups which have ten pairing samples respectively.Based on the relationship between standard deviation and expected variance,evaluate the sample preparation precision.Test the bias of mechanical sampler when the precision is qualified and the test enough data with enough pairs and independent have no outliers.The results show that the verification bias is less than the maximum tolerable bias,the results gotten by coal mechanical sampler are representative.