Abstract: Based on datasets of cloud base height (CBH) detected by the laser ceilometer (CL51) and the microwave radiometer (MWR-IRT) with the infrared thermometer from 13 August 2016 to 31 July 2017, we have performed the comparative analysis on the differences of CBH from CL51 and MWR-IRT, and discussed the observed performance of CL51 and MWR-IRT to CBH under different weather conditions. The results show that the recognition results of CL51 to low-and middle-cloud are basically consistent with that of MWR-IRT to, but there are certain differences in the their recognition results to high cloud. Under cloudy cases, the CBH detected by CL51 is basically consistent with that detected by MWR-IRT, whose annual mean CBH values are respectively 1.91 km and 2.03 km, and the two recognition results have a high correlation with a correlation coefficient of 0.65. With respect to MWR-IRT, CBH detected by CL51 is higher to high cloud but is lower to low cloud. In addition, under different weather conditions, CL51 and MWR-IRT show different CBH observational performance. There are significant differences in their observational performance to CBH under fog cases and heavy haze cases, slightly differences under light fog cases, but there is basic agreement under no fog or haze cases, fog and haze cases, light haze cases and medium haze cases.