Abstract: The Baiyangdian Lake is located in Xiongan New Area, which has a fragile ecological environment and a shortage of water resources. Lake evaporation is one of the main discharge of the Baiyangdian Lake, and research on lake evaporation is of important practical significance and scientific value for understanding lake water circulation and evaluating ecological water demand and for recovery of lake ecological function. However, the actual observed data on evaporation in the Baiyangdian Lake is limited, so it is usually estimated by converting the data of nearby land observation stations or empirical models, which cannot accurately estimate the lake evaporation because of large calculation error. In this work, in-situ experiments were carried out in the Baiyangdian Lake. This study established an E601 evaporation station and a 20 m² evaporation pool to observe the lake evaporation at the center of the Baiyangdian Lake, and an automatic weather station was established simultaneously to get meteorological data. The correlation between evaporation by E601 evaporation station and meteorological factors is analyzed by methods of correlation analysis and multiple linear regression model. The evaporation of the E601 evaporation station is compared with the data of the 20 m² evaporation pool and the simulated evaporation. The results indicate that in the Baiyangdian Lake in summer, the diurnal variation of lake evaporation is intense, ranging from 0.4 mm/d to 6.6 mm/d, and the maximum evaporation occurs in June, but decreases with the increasing rainfall from July to August. Evaporation of lake water is more affected by radiation and humidity. The evaporation of 20 m² evaporation pool is taken as the evaporation of lake water. The observed evaporation of E601 evaporation station is higher than the actual evaporation of Baiyangdian Lake, which can be used to estimate lake evaporation more accurately by local evaporation conversion coefficient. In this experiment, the evaporation conversion coefficient between the 20 m² evaporation pool and the E601 evaporation station is about 0.98, which is slightly greater than the previous studies. The results of this study provides a basic basis for the calculation of water surface evaporation in the Baiyangdian area.