The invention relates to a simulating device and a simulating method for groundwater seepage near a coastal zone under the effects of earthquake and sea tide. The device is mainly composed of a constant water head water supply device, a seepage tank, a tide generator, a salt water tank, an earthquake simulating shaking table and simulation well steel tubes, wherein the tank body can be divided into a fresh water area, a water-containing medium area and a seawater area along the length, for the water-containing medium area, water and sand are added for constructing a pressure-bearing water-containing layer, the medium of a water-resisting layer is clay, and in the salt water tank, tap water in which NaCl and carmine pigment are added is used for simulating colored seawater. According to themethod provided by the invention, the tap water is injected into the fresh water area through a constant water head and is injected into the seawater area through the tide generator; when the seawater wedge is stable, the frequency, acceleration, waveform and principal earthquake time are set on the earthquake simulating shaking table, vibration waves are loaded for starting a vibration seepage experiment, monitoring data is collected in real time, and the change process of the fresh-water-salt water interface and the water level of a pressure measuring pipe is observed. With the device and the method provided by the invention, the objective simulation and representation for the dynamic change of groundwater under the effects of earthquake waves, sea tide and the water-containing medium can be realized.