In the development of optical clocks, the absolute frequency measurement of the optical clock transitions and the comparison of different kinds of optical clocks are important steps or applications. It is also important preconditions for the reorganizations of optical clock as the secondary representations of the SI second. Calcium ion optical clocks with both uncertainty and stability at the E-17 level have been built in Wuhan institute of physics and mathematics, Chinese Academy of Sciences(WIPM), the absolute frequency of the calcium ion optical clock has also been measured via the GPS system. The measurement result is adopted by International des Poids et Mesures (CIPM) twice as the recommended frequency value of the calcium ion optical clock transition; the result hasn’t been chosen as the secondary representations of the SI second due to the relatively low measurement accuracy. In the meantime, National Institute of Metrology(NIM) has built a strontium optical lattice clock with an uncertainty at the E-16 level, the absolute transition frequency of the clock transition has been measured referenced to a cesium fountain, the measured result has been chosen as the secondary representations of the SI second. For the above reasons, here we give our proposal. We plan to transprot the calcium ion optical clock from WIPM to NIM. The cesium fountain will be used as a reference to measure the absolute frequency of the calcium ion optical clock transition, the comparison of the calcium ion optical clock and the strontium lattice clock will also be made. With the implementation of this project, the frequency ratio of different kinds of optical clock frequencies will be given, the absolute frequency of the calcium ion optical clock transition will also be measured with higher accuracy, which will make our country more competitive in the time and frequency standard regime, making our contribution to the upcoming redefinition the SI second.