Test methods for stone powder content (hereafter referred to as SPC) are quite different between the 2001 version and 2014 version of Code for testing aggregates of hydraulic concrete. In order to investigate the influence of method change on SPC test results, we detected 535 groups of artificial limestone powder (hereafter referred to as ALP) from Huangdeng hydropower station by different test methods. Results indicate that the measured values of ALP are quite different by different SPC test methods, and the influence of test method is of some regularity. The deviations in SPC test results obtained by wet screening & washing method and dry-sieve method accord with normal distribution, and the measured values of micro-particle content of ALP by wet screening & washing method also follows normal distribution. Moreover, the deviations in ALP test results obtained by the two methods in normal concrete mainly varies from 5% to 9%, with the mean value of 6.7%; as for roller compacted concrete, the interval is from 4% to 9%, and the mean value is 5.2%. In addition, the proportions of micro-particle content in ALP in normal concrete and roller compacted concrete are identical in general, approximately accounting for 80.4% of SPC.