This paper analyzes the relationship between the Sampling Rate (SR) and Sampling Loss Rate of Elephant Flows (SLREF) of hardflow. Then two improved algorithms are proposed to reduce the ratio of SLREF to SR(rd ). The relative error and the parameters setting are discussed with various sampling buffer sizes and various measurement periods. Compared to the hardflow, the results show that rd of the two improved algorithms decrease 1.4 and 6.6 respectively when SR is low (e.g. 4.5%). Furthermore, all rd incline to zero when SR is large (e.g. 11.3%).