Effectiveness of wetland conservation is a reflection of the quality, health and threatened situation of wetland ecosystem after the implementation of wetland conservation policies and measures, and also an important reflection of the degree of achievement of wetland protected goals. Ecological pressure is an important factor affecting the realization of the wetland protected goals. It can be evaluated from the perspective of wetland ecological pressure, state, and response. Lake Shengjin is a typical floodplain lake in the middle and lower reaches of the Yangtze River, which has been facing ecological pressure caused by human factors for a long time, which has seriously affected the achievement of wetland protection goals. In this paper, Lake Shengjin was taken as the research object, and the 0.01°×0.01° longitude and latitude grids were taken as the evaluation units. Ten negative indices and five positive indices were selected in this area. The index system of conservation effectiveness was established based on the Pressure-State-Response (PSR) model that can be used to evaluate the conservation effectiveness of Lake Shengjin in the past 30 years from 1989 to 2019. Results show that the conservation effectiveness has declined in the past 30 years, with the proportion of very effective level grid units decreased from 32.50% to 11.07%, and the ineffective conservation level increased from 3.57% to 8.57%, and the middle level accounted for a large proportion, and the proportion of ineffective level was the least in all the 30 years. From the perspective of functional aeras, the conservation effectiveness of the three functional areas decreased in the past 30 years, and the conservation effectiveness of the core zone is higher than that of the buffer zone and experimental zone. From the perspective of the administrative village units, some sites have low conservation effectiveness, such as Chang'an Village in Dongliu Town, Donghu Village, Liulian Village, Tanghe Village, Bailian Village in Zhangxi Town, and these villages mainly distributed in the buffer zone and experimental zone, and the main ecological pressure is reclamation, and these villages need to strengthen the supervision of ecological pressure. The dominant ecological pressure factors in different periods are different over the past 30 years. The main ecological pressures were reclamation in 1989, dikes in 1999, purse seine in 2009, and still the original reclamation and dikes after removing the purse seine in 2019. It is suggested that the grid monitoring and management unit should be implemented into the administrative unit, and the apanage management should be strengthened through establishing the management system of the river, lake, and forest chief, to control the ecological pressure and enhance the management and conservation effectiveness of wetland protected areas.