The progress of cesium fountain clock at NIM

NIM4 cesium fountain clock has been operating stably and sub-continually for more than 2 years. We in this paper present the improvements of NIM4 clock in 2004–2005 and most recent evaluation for its systematic frequency deviations during 7–8,2005 resulted an uncertainty of 5E-15. We also report the construction of NIM5 movable cesium fountain clock at NIM.