In view of an investigation of the resistance characteristics brought about by the rapid increase of velocity and the related factors, the local resistance test has been carried out by using transparent plexiglass circular tubes with sudden velocity increase ratios of 25:1 and 4:1 respectively, with experimental devices of different incoming turbulence degrees adopted as well. The experimental results show that the drag coefficient of the tube decreases sharply with the increase of Reynolds number, subsequently decreasing gradually with the increase of Reynolds number until it remains constantly unchanged. With the increase of the turbulence intensity of upstream flow, the local resistance coefficient decreases due to the advance of reattachment point of separated flow within the range of Reynolds number measured in the test. The local resistance coefficient of the tube with sudden velocity increase is not only related to the sudden velocity increase ratio and sudden contraction structure, but also negatively related to the Reynolds number under the design velocity in the tube. The experimental results subvert the traditional empirical formula that the coefficient of resistance of sudden shrinkage is independent of Reynolds number in the classical textbook, but rather it has a certain reference significance for the accurate evaluation of the total resistance in the process of pipe network design.