Abstract: Based on the present situation of oceanographic instrumentation, in order to get the quantitative results of the Conductivity-Temperature-Depth profiler (CTD) function and actual use, “In situ comparison-testing and standard inspection procedure for applicability of oceanographic monitoring equipment (the National 863 Program)” was carried out in the northeast South China sea. The test was a thirdparty independent testing. It aimed at inspection and verification of the domestic CTD which is a matured technology for commercial production. In the field test, all CTDs were bound together in an iron frame and then measured simultaneously. During the test, we used a simple method called phaseshift correlation analysis to match the data of parameters, including pressure, temperature, conductivity and salinity data of domestic and standard CTDs. According to the test in situ, the data curves between the two CTDs were approximately identical and coincide. The actual precision of the two domestic CTDs were close to their nominal specification, but lower than the standard CTD. This program will advance the perfection and finalization of technology and raise the reliability, stability and uniformity of the equipment. It is believed that the results will provide supports for the massive application and promotion of the domestic CTD.